Like most things in crappie fishing it can be done many ways. Most always with a slip float, with either a bobber stop or depending on the depth, just use the little pin that comes in a six pack of the cheap floats.
Use a float appropriate with the weight to be used. Put the bobber stop on the line, a bead then the float, attach one or two jigs or if using minows just hooks and split shot as needed.
A lot of people use them in the rear so they can get the bait furthur from the boat, especially if the fish are shallow.
I saw a man in Georgia with 8 16 ft poles. Fishing them from the front. His floats were about 18 inches from the end of his rods and he was fishing two jigs, the deepest was 3 ft.
I talked with him several minutes. He always fishes that way, but he doesn't fish fish over 12 ft. deep.
I live in NC and rarely see that rig here. It is more common farther south.
It is not uncommon for the front person to be traditional tight linning and the rear to use floats.
With a larger float a 1/2 oz sinker can be used to allow greater speed, without having the line go straight back.
Some people using the rig on the front say it allows them to see the bite better and some just put a free running float on the line for that purpose.
Hope this is halfway clear. I blowed my mind the first time I saw I saw it and the resuts I saw with it on Lake Oconee in Georgia. Course I was then , and still am a dumb NC ridgerunner, but a little smarter one now.