All the ones I have ever done were 2 inches thick and cut to around a foot long. I placed them in plastic pots and used 1/2 topsoil and 1/2 sand so they stayed in place. I put them into the substrate about 3 - 4 inches deep. Over them I put a large clear plastic container from pretzel bites. Put a tray under the pot and wet it down well, put some air holes around the plastic container, remove daily and water. Mine were in morning sun only so they only needed water once a day. I left a few leaves on them and honest I was just flying on instinct. It worked though and I had root in 4 - 5 weeks. There is probably a few places that have proper instructions if you google for them, but that is what worked for me.
Grimmy