This shows how to fix them to your line.Torpedo – Cralussowww.cralusso.com/angol/torpedo.php
I put my olivette or bulk 1″ above the bottom and have my hooklink laying on pinned down with a shot halfway between loop to loop and hook. You want to bulk it so the whole body of the float is submerged with just the bristle visible. If it is pushing hard you may need to over shot it. I use it as a static rig on the pole holding it back and occasionally inching it forward. Bites are unmissable, it either slowly buries or the body comes up above the surface if the bulk gets lifted by a fish.
You need to have at least 3ft of line between pole tip and float and hold the pole tip low to the water. Expriment a bit and find the ideal pole angle so the float body is submerged and not riding up in the water. I find the 1gr is perfect for 4-5ft deep swims. I have used 6gr on the Thames in 12ft of pushing water and needed an 8gr olivette to make it effective. It does take a bit of practice to know how these floats work best but they certainly can give you the edge in faster water where using feeders or wagglers would be futile…