ok, so i saw that u can make special ranks, but are they the same as a admin, or do they do almost the same things?

Ranks have nothing to do with groups.

then what is the difference between a rank and a group

Major difference is groups can be given permissions. i.e. which forum they can view , vote, etc etc.
Ranks are just images which you can give to the user under their avatar. They can either be special ranks or ranks which are changed automatically after a certain number of posts.

so can the rank can do the same thing as an admin can?

No, the ranks mean nothing, its just an image to show your position of the forum.
Example: I could be given an administrator rank on this forum, and I wouldn't have access to the admin panel, or the moderator's tools.
It's just a fancy image.

The only way someone can do what an admin can do is if u add them to the admin group.
You can set permissions via groups.

ooo, ok thanks. lock and solved please