Drive the front wheel up the ramp and stop. Line up the back wheel with the ramp if it is not already. It needs to be exactly in line otherwise it may climb up the side of the channel and fall off. It's quite easy to hold the bike like this - leave it in gear and use the clutch and front brake to control the motion. You don't need the back brake.
When everything is lined up properly, start the bike and drive it quickly up the ramp, stepping smartly aboard while holding it upright.
I secure the bike to the port side shrouds, and cover it with a tarpaulin to keep spray off. In heavy seas this area can get very wet, and salt water is not good for bikes. I have not had the motorcycle aboard in these conditions but I used to keep a bicycle there and it was seriously degraded by the experience. Now I keep it across the stern, but that's not an option for the motorcycle (unless I built a special rack for it).