[Kaneki Ken]

First I suggest learning PHP, JS, HTML and CSS. Because honestly, you're going to be doing a hell of a lot of programming if you want to make a forum and have it be good. HTML and CSS only takes 3-4 weeks to really get into the intermediate level (at least for me it did, I had dedication so yeah), PHP and JS would take months to get to intermediate.
Adding everything together.... I'd say a year or two to actually know some of the languages. I want to say 4 years to become a "master" at it but you can never really master a programming language. And regarding your icons there's a plugin for that, just go digging around and you'll find it. Regarding the tabs, that's also a plugin, again go searching and you'll find it. Hard work and dedication or gtfo basically. Stop trying to take the easy way or you'll never learn anything.