Hello!
Welcome to the friendly world of roleplay online, RPol!
To answer your question about coding. Most coding you would use is always at the bottom of the window you are writing your post in. Such as bold, italics etc all just below the window for you.
One major thing to remember is read ALL the rules and FAQs, each forum such as Wanted Players, Wanted GMs, etc have the rules for that forum at the top.
There is a search games on the main page. You’ll find loads of system games like 3.5 there.
Enjoy the experience!