Take the plugs out,
remove the oil pressure relief valve from the lower front of the RH crankcase,
fill tank with oil,
continue to turn over engine (by foot or hand), until oil leaks out of the tapped hole that the relief screwed into.
After a few more kicks, replace relief valve, and wipe up spilt oil.
Replace plugs, run engine, check oil is returning to the reservoir, and check oil level.
Go out and ride, sharing the beautiful noise with all.
Richard