Hi. Sorry english is not my native language.
What I call the compression plug is the insert that goes inside the fork. You can see in the picture that is not going down any further in the fork, so I can´t put the top of the stem.
Thank you for the explanation, I wrote to Vb and they will send me the missing part.
And I will attach a picture with the seat post issue. To clamp the seat, you need a screw and 2 parts. Onepart must not be threaded, only the one in the end of the screw. Mine are both threaded

Yeah I don´t have that piece that you marked in the picture. Thanks for the info
Also they sent me 2 threaded pieces for the seat rails, so I can´t adjust the seat to the seat post.
And I had to file the steerer tube because the compression plug won´t sit in the tube, it got stuck halfway.
So I´m having some issues before I can even ride it.
Hope I will ride it someday.
Thanks