Remove the screen completely. Do not lose any bits.
The countersunk bolts go through the round holes of the tobinators and holds them to the original screen mounting bolt holes on the bike (little black bits). The tobinators are mounted with the SMOOTH side facing FORWARD.
Where the original BMW adjuster screws go through the SIDE of the screen, there is an OVAL hole. You need to file these holes in the screen out so that they're ROUND.
The bolts that you've circled go through the screen, then through the long slotted holes, then through the "D" shaped threaded pieces. The plastic washers go either side of the screen.
The missing bolts are IIRC M5 and approx 30mm long. Long enough to go through screen, tobinator and "D" section bits. Also allowing some extra so that you can loosen the bolts to allow the screen to be adjusted.
You only need 2 long screws. You get 4 in case you lose one or two.
Hope this helps.