I recommend picking up a book on MySQL that goes more in depth on table design, MySQL features, etc. than a book that talks about MySQL and PHP. The very first database driven website I wrote didn't have a single table join in it because I didn't even know they existed, which I still get a good laugh out of. There's also a lot of common tasks you'll try and accomplish in PHP code that you can do more easily in MySQL; in other words, the amount of "programming" code you can move into database logic is astonishing and something every programmer should be aware of.
The only reason I say this is because of this statement:
"Since clans will have multiple members use the leaders id that registered it?"
We all need to start somewhere, but a good book should help answer 95% of the initial questions such as those.
However, if you don't want to buy a book, I suggest something like the following:
table {field1, field2, field3, ...}
users {id, login, password, ...}
clans {id, name, ...}
clan_member_ranks {id, name, ...}
clan_members {clan_id, member_id, rank_id, ...}
