MyBB Community Forums

So basically if I want phpos.org and forum.phpos.org to look the same. I am a web designer/developer so its not going to be a problem. But I want to make sure I edit the right files... so I can edit the header of mybb and add the CSS files. Is that correct? Or are there additional steps I would need to integrate? Thanks!

For your main site (if it uses a template) you could edit its HTML attributes. And for MyBB, you could alter the header templates as per your liking.