Yup. Pull clutch lever in and operate kick start until clutch plates are free (they often are already, but it's good discipline and a wise precaution against the day they're not (it's only the oil that makes them a bit sticky)). Turn fuel tap on. Tickle by plunger on carb (prime like a lawnmower) until a visible dribble comes out of the carb and smells nicely flammably dangerous as it goes earthwards. If fitted with manual advance and retard, retard at least half way ie pull lever towards you (normally) to avoid it kicking back at you; if fitted with choke/air slide (loads of us don't bother) close it if the engine's cold. Then, a whiff of throttle, not too much, and a decent kick . . . . and hey presto. When hot, forget choke slide - ie leave it open - don't tickle the carb (unless the thing won't go straight away), and just kick it. . . . Sometimes in the twilight zone between hot and cold, the thing might not want to go . . . in which case, a gentle tickle of the carb usually does it.
However, it does have to be said that a tentative or gentle exploration of the lever's arc, accompanied by pleasantries about the aesthetics built-in by the nice man at BSA, is not what's required. That leads to a sore right foot as the thing spits back, mocking the inept. A firm, smooth, determined, full-length prod is necessary to emphasise who's in charge here. If in doubt, eat more and gain a few kilos! Dominance never felt or sounded so good . . .