The split shot rig is nothing more than clamping a round split shot directly on the line between 8" to 24" above the hook. You can google the name Dick Trask and read whatever is available, he is known as the father of the split shot rig in regards to tournament bass fishing.
Another bass nobler who wrote about the split shot rig is Bill Murphy, author of "In Pursuit of Giant Bass" IMO one of the bet books ever written on bass behavior and location in deep structured lakes. Bill liked to stitch retrieve his split shot worms.
IF you search the main page "split shot" there is a lot to read on the topic.
The modification that I like to use is called "slip shot" , also search that and read lots of stuff posted.
The key to split shotting is round split shot about 3/16" to 1/4" in diameter. You clinch the shot on the line, then slowly pull the line through the split shot and up the line about 36", cut the ldamaged line off (any flatten line) tie the hook on using a Palomar not or if using FC line double the Palomar knot or use a knot you like. The hook depends on the line size and worm size, I like Gamakatsu #11 worm hooks for this rig.