If you are looking for joints for concrete slabs on grade, one of the better references is "Concrete Slabs on Grade", published by the Portland Cement Assoc.
Expansion joints are rarely needed. Control joints are almost always needed. General rule of thumb is the joint spacing should be about 24 to 36 times the slab thickness (that will be in inches). Joints should be saw-cut to a depth of about 25 percent of the thickness and should be cut THE DAY OF PLACEMENT! If you wait until the next day, it's too late. Cut the joint as quickly as you can get the saw to cut without raveling the joint.