Should i do one set of something, then move on to another set of a different exercise.
If you find that that works well for you, yes.
Or should i do all 3 sets of one exercise in a row?
If you find that that works well for you, yes.
Try both. I have. I like the second option better personally, it work best for me. On the other hand my training partner never does only one exercise at a time, always 2 or 3. He has had great success. (he is the #1 ranked amateur strongman in the US)
You will have to try both to find out what your best bet is.
If so how much rest in between?
That one you will have to play with as well. Chillin is right, manipulating rest periods is a great way to make a simple change to your workout to push you into getting better results.
You will find that sometimes you are better off with longer rest periods, other times you are better off with shorter rest periods. A lot will depend upon the reps, amount of weight you are using, as well as your training experience. (Chillin hit on this one as well)
With all your questions you will find all different combinations of training will work for you at some point in your training career. That is part of the fun of training, learning about yourself and what you have the greatest success with.
The only way to get your answer is to train hard and make changes as you progress in your training experience.