When you install these. I'm pretty sure they should install to the correct folders for you. All the proper .dll's keywords for the IDE should go to the proper places. I have not had any issues thus far.
If you have any issues just as MrV said I would look into the plugins doc folders, or just run the example. Such as in the physics folders. These ad-ons/plug-ins are adding features to DBPro and more as far as source goes and more options for coding.
rem allow user create game with one click
rem create graphics, sound, scripts, models, with one click
rem slap user in face if game choice is mmo