Php And Mysql Help

Im Using A Bulletin Board System MyBB And I'm Trying To Code In A Login System To The Main Site ...
would it work if i took the login code and pasted it on site?
Also Looking For Scripts To Buy...
Im A Noob At Mysql So Thats why not a lot of infomation :S

You want to log into the forum from a form on the main page?

Just use the same HTML form code, will probably work.