Popping over from the 3rd gen side of the forum. I have a different problem than you, but the booster/ABS assemblies are very similar and I have documented the disassembly if you want to swap your ABS solenoids and pressure switches yourself. Check out post #14 in
this thread for the process of removing this 'black box' assembly along with more information on how all this works.
I am unfamiliar with the ABS solenoids themselves, but the process of removing the black box is done from the MC side, not from underneath the plastic cover. There are screws underneath the cover but you do not want to separate the black box from the aluminum valve body that it is mounted on. If you remove the valve body from the MC, you will of course need to bleed it after, but this can be done at home. Hope that the visual documentation helps you understand how it all goes together.