how to hide fabric/clothes gaps and junctions on walls?

[lucaflea]

hi.
this is my firs post here...

i'm wondering how do the pros do this:
the insulate walls with rockwool (or similar) and over it they use fabric.
it seems they "push" the pannels into the wall because i can't see screws or pins.

how do you do this?

sorry for my poor english...

ps: this is my littles studio... http://www.altramusica.net/docs/recording-studio, if you want to suggest me some improvements.

happy new year!
luca