Assuming you are using the current stable v11.x TKL appliance (and if you're not then go do that), on first boot you should be asked for 2 passwords: The root (Linux admin account) password, the other should be for eXtplorer admin user.
The root password can be used for logging into the local terminal, SSH, SFTP, WebShell (Shell-in-a-box) and Webmin (username: root). The eXplorer password should get you into default eXplorer (username: admin) - although IIRC you use root (or another Linux user) to access the webFTP part of eXtplorer.
Which particular password are you referring to?
Assuming you are using the current stable v11.x TKL appliance (and if you're not then go do that), on first boot you should be asked for 2 passwords: The root (Linux admin account) password, the other should be for eXtplorer admin user.
The root password can be used for logging into the local terminal, SSH, SFTP, WebShell (Shell-in-a-box) and Webmin (username: root). The eXplorer password should get you into default eXplorer (username: admin) - although IIRC you use root (or another Linux user) to access the webFTP part of eXtplorer.