You don't need step 2, actually you must not do anything like step 2 if you want to use contrib.auth
You also don't need to create first/last name fields as you mentioned in step 3 as contrib.auth.models.User already has them. See my comment above for more details on that.
You also don't need step 4, contrib.auth handles that for you.
Regarding step 5, I'm don't think using a tuple will work. It should be a string, see the post for an example.
I'd recommend re-reading the post a couple of times, and if something isn't clear let me know and I'll elaborate. If something isn't working, feel free to ask and include code snippets.
You don't need...
You don't need step 2, actually you must not do anything like step 2 if you want to use contrib.auth
You also don't need to create first/last name fields as you mentioned in step 3 as contrib.auth.models.User already has them. See my comment above for more details on that.
You also don't need step 4, contrib.auth handles that for you.
Regarding step 5, I'm don't think using a tuple will work. It should be a string, see the post for an example.
I'd recommend re-reading the post a couple of times, and if something isn't clear let me know and I'll elaborate. If something isn't working, feel free to ask and include code snippets.