If you'd like to develop your own forum board, you must first realize this may take months of long hours and a lot of frustration as it will have security exploits, bugs, errors and messy coding.
If you're a newcomer to PHP, it'll be even longer since you first have to work your way around it learning what and how it works and the functions. I suppose getting a degree would help a lot since that's great, doing online tutorials, buying books also help just as much, you should look into those as well.
Forum boards take time to build, you'd require pretty much
[*]Profiles
[*]Categories
[*]New Topic/Posts
I can probably go on forever, allowing users to upload avatars, edit their own signatures, have their own little "blurbs" or about me's, their own locations, own ranks. It's a long process.
A quick solution if you don't want that is looking at the vast majority of forum boards that are already developed and have been out for quite some time, which are for example, phpBB, MyBB, SMF, vBulletin (costs money). All are great.
Good luck.