TIA Portal multiuser

[Forti]

Hello!

I'm very new to the TIA Portal, and i need some answers about Multiuser service.

In the near future i need to program some PLC's with TIA Portal with my co worker simultaneously..
He told me that he  doesnt know, how this will work, because he dont know how the multiuser server works (+ needs license maybe?).
In Step 7 we can program the PLC simultaneously, i just upload my FC to to PLC, and he works in another FC. He said that this is not the case with TIA Portal, and instead we need to exchange our projects frequently.

But is it true? I need some license for this, and do some extra work, to work together with my co.worker?
I only want to load my FC's into the PLC and my colleague load in another Fc's,DB's, etc..

Sorry for the beginner question, i never worked with TIA Portal.