EDITING YOUR PROFILE:
In the User Control Panel (the top bar says "Profile", which allows you to edit your profile), you can change numerous stuff.
I don't know if you can change your username (as I'm the admin), but you can (probably) change your e-mail address and password. These are all required.
Several options are optional, but Gender and Birthday are not optional. Comments are, to my knowledge, editable by moderators and admins, and the Tokens thing depends on posts that was thanked by admins (the thanks button is probably one that says "merci"). You can also set your contact details (websites, ICQ number, Skype, etc) on this page.
Here, you can change preferences. There are also options available that will notify you if you get ninja'd, and allow you to be a ninja by hiding you from the online list (but admins will always see hidden members, as far as I know).
It's fairly obvious: you can enter a signature here.
Also obvious: you can change your avatar. It's size must be 64 KB or less, and it must be 200 x 200 pixels or smaller. There's also a gallery with pre-uploaded pics.
FRIENDS AND FOES page:
Here you can send friend requests to other members, or put members on your ignore list (where the FOES part fit in). However, you don't receive notifications (as far as I know) so you'll have to check every now and then.
TOPIC(S) BEING WATCHED page:
... Insert description here. I don't use it so I have no clue what it does.
I also don't use it, but I think it's related to "favourite threads" or something.
CHARACTER SHEET page:
Here, you can edit your character sheet. Several options are admin-changeable only (to my knowledge), but some of them can be changed by the member self. And members can generate their own sheets as well! See the Character Sheet thread in the RPG subforum for more information.
I casually administrate the Symforá GX forums.