Anyone working with unity3d??
What are the main topics that I should look for, in order to get a good introduction for usage a working with unity3d??

uf its a tough one... i startet by looking at some of the complete projects and free asset packs in the asset store... for something specific i recommend checking out some video tutorials on the subject. but in the end, just playing around with it gives you a good start.

It is not for me, the thing is

I just learned working on unity at my class, in college
My boss liked the idea and want to start a project on unity that will be a VR thing, he told me to learn it and I will have to make a presentation to introduce my coworkers to this invention

There are many example projects that Unity provides as well as tutorials. It may also be worth your while to read through the documentation and familiarise yourself with some of the things you can do from within scripts. I find the best way to learn is to create a couple of different small games and slowly build on then as you learn new things.