The process is the same for both A1 and A2 versions. The dust cover is currently tested only with the Bulltrigger 2 installed on SSG10's by default.
1) Remove the receiver assembly from the stock. 3 screws on the bottom. You can follow the Novritsch Maintenance video here.
2) Unscrew the safety switch screw. Remove the spring and switch itself. If the black cylinder part unscrews together with the spring and screw, don't worry. Just take some pliers and unscrew the screw from the cylinder part just like a regular nut.
3) Take the safety switch dust cover and place it so that the two notches alight with two holes on the trigger. Re-install the screw and tighten it down.
You're done 🥳!