Insulation of upper floor ceiling

Hello dear members :)

Can someone explain to me how the attic conversion of a tent roof with a nail plate truss construction works?

Specifically, I am interested in the installation of the OSB boards to make the attic space walkable. Simply laying them down is not that easy since the vertical trusses are constantly in the way.

Is an additional structure made between the main beams on which the OSB boards rest?

Thanks in advance for your answers :)

With us, it was called the Stauraumbinder. In the middle section of the attic, there is an area of 3x14m where no vertical beams run.