From your comments it sounds like you perhaps have hosted (shared) webspace (see below)? If so you may need to contact your host (or post on their support forums if they have them) to discuss installing WordPress on your shared server.
As for WordPress, I don't know anything about localising WordPress. Some software can change language relatively easily (by simply changing a setting in a control panel/admin area). Others require a specific install in the desired language. I suggest you do some research around the specifics of WordPress. Try this for starters: http://www.google.com/search?q=german+wordpress
Beyond that you need to decide whether your current setup is adequite. Do some research around what web serving options are available and what will be the most appropriate for you. That will somewhat depend on the nature of your website and how much direct controll you want/need (and/or can handle). You will no doubt have local options as well as global ones and your final choice will need to be based on considerations around what your website is about, how critical reliability is, anticipated traffic and where people will be accessing your site from. Cost will also be a factor no doubt. All methods have pros and cons. Here are the main basic options:
Hosted (Shared) Webspace - This is when a web hosting company provide you with space on a shared server. You have limited (or no) opportunity to interact with the underlaying system. You will often administer your system with some sort of web based control panel. Cpanel seems very popular. The options for software and configuration will be limited by the hosting company and you will find significant variation company to company; price range to price range. You will only need basic web server knowledge to use a service like this, although you are also very limited in what you can do with your webspace.
VPS (Virtual Private Server) - This is where you have your own private virtual server. The hosting company still take care of the hardware and the underlaying OS. You have full control of your virtual machine and will need some basic server OS knowledge to use a service such as this. AWS (Amazon Web Services) EC2 (as provided via the TKL Hub) is an example of a setup like this.
Dedicated server - This is where you have your own physical server in someone else's datacentre. These can vary from leasing hardware where you never physically go to the datacentre, the datacentre staff take care of the physical machine, but you have complete control of the whole server yourself. The opposite extreme in this situation, is where you provide your own physical hardware and provide your own maintenance, the datacentre only provides the infrastructure to support your webserver (eg power, high speed internet, cooling, etc).
Self hosting - This is where you take care of everything yourself. You cna use either a physical machine or a VM running on a Hypervisor OS.
TKL is only relevant to the last 3, and even then VPS will depend on whether your hosting company are willing to provide TKL images to install from.
Beyond these pointers; the language barrier combined with your lack of knowledge in this field make it beyond the scope of volunteers such as myself to help you out any further. I suggest you go away do some research and decide which is the best approach for you and your unique usage scenario. If you decide you'd still like to use TKL, then do some research around WordPress and basic Linux server admin and come back and I can try to help you from there.
If doing that level of research or self directed learning is not something you have time or energy for than I suggest you hire a consultant to help you out. Good luck :)
Sounds like you need to do some research
From your comments it sounds like you perhaps have hosted (shared) webspace (see below)? If so you may need to contact your host (or post on their support forums if they have them) to discuss installing WordPress on your shared server.
As for WordPress, I don't know anything about localising WordPress. Some software can change language relatively easily (by simply changing a setting in a control panel/admin area). Others require a specific install in the desired language. I suggest you do some research around the specifics of WordPress. Try this for starters: http://www.google.com/search?q=german+wordpress
Beyond that you need to decide whether your current setup is adequite. Do some research around what web serving options are available and what will be the most appropriate for you. That will somewhat depend on the nature of your website and how much direct controll you want/need (and/or can handle). You will no doubt have local options as well as global ones and your final choice will need to be based on considerations around what your website is about, how critical reliability is, anticipated traffic and where people will be accessing your site from. Cost will also be a factor no doubt. All methods have pros and cons. Here are the main basic options:
Hosted (Shared) Webspace - This is when a web hosting company provide you with space on a shared server. You have limited (or no) opportunity to interact with the underlaying system. You will often administer your system with some sort of web based control panel. Cpanel seems very popular. The options for software and configuration will be limited by the hosting company and you will find significant variation company to company; price range to price range. You will only need basic web server knowledge to use a service like this, although you are also very limited in what you can do with your webspace.
VPS (Virtual Private Server) - This is where you have your own private virtual server. The hosting company still take care of the hardware and the underlaying OS. You have full control of your virtual machine and will need some basic server OS knowledge to use a service such as this. AWS (Amazon Web Services) EC2 (as provided via the TKL Hub) is an example of a setup like this.
Dedicated server - This is where you have your own physical server in someone else's datacentre. These can vary from leasing hardware where you never physically go to the datacentre, the datacentre staff take care of the physical machine, but you have complete control of the whole server yourself. The opposite extreme in this situation, is where you provide your own physical hardware and provide your own maintenance, the datacentre only provides the infrastructure to support your webserver (eg power, high speed internet, cooling, etc).
Self hosting - This is where you take care of everything yourself. You cna use either a physical machine or a VM running on a Hypervisor OS.
TKL is only relevant to the last 3, and even then VPS will depend on whether your hosting company are willing to provide TKL images to install from.
Beyond these pointers; the language barrier combined with your lack of knowledge in this field make it beyond the scope of volunteers such as myself to help you out any further. I suggest you go away do some research and decide which is the best approach for you and your unique usage scenario. If you decide you'd still like to use TKL, then do some research around WordPress and basic Linux server admin and come back and I can try to help you from there.
If doing that level of research or self directed learning is not something you have time or energy for than I suggest you hire a consultant to help you out. Good luck :)