Go to your local hardware store, and get a handful of drywall screws, and appropriate screw for them (they are often sold together in box of eg 10). Mark the wall, use 1/4" drill bit, and insert the drywall screw, then screw in the metal screw to hold on the speakers.
While you are at that store - look for some cable channels where to hide the wires. Most of them come with sticky tape already taped, ready to be glued to the wall.