You can make a functional darkcloth out of an old black sweatshirt or something like that. The neck goes around the camera, you stick your head from the bottom as if you were going to wear it. I presume your cameras have focusing hoods, that might be sufficient for your first few shots. Try your loupe and see if it works. You just use iit against the ground glass and check your focus with it. Its easier with a darkcloth. Cable releases are really necessary. I use a stopwatch for long exposures but you can use whatever you have. Know about bellows extension correction factors before doing work closer than 10x the focal length. That should get you going.