A couple of things here.
First, the bridge pickup problem.
1 - if the stereo/mono switch is in stereo mode and you have a regular mono guitar cable plugged in, then you are only going to get one pickup. That may be why you're not getting the bridge pickup. Try it again after moving the stereo/mono switch.
2 - if that isn't it, then it may be that the pickup selector switch is pointing to the neck pickup. See below for the selector switch problem and if you get that fixed then maybe that will address this problem.
3 - if that isn't it, then remove the back plate from behind the control cavity and make sure both pickup leads are securely plugged in to the pc board.
Second, the pickup selector switch should not be moving 360 degrees.
1 - take the back plate off behind the pickup selector switch. Move the switch on top while watching underneath. Is the whole pot moving?
2 - if so, you'll need an .050 Allen wrench (hexhead wrench). There are two hex screws that hold the knob to the shaft. Carefully loosen these screws (you don't need to take them all the way out; they are very small, if you drop them on the carpet it might raise your frustration level). When the screws are loose, the knob can easily be removed from the shaft. At this point you may find that the nut is not tight on the shaft. You'll then need a 1/2 wrench or nut driver to tighten the nut on the shaft.
3 - if the pot is not moving, then it may be that the knob itself is loose, in which case you can tighten the hex screws on the knob as in 2 above.
Please let us know if this was helpful.