Upon receiving it'll probably work like a charm, don't worry!
As everything with moving pieces and unsealed, it will get dirty by using it and it may end up acting strange. I don't know much lights which are completely maintenance-free, but some people are lucky and their lights always work when they should, even if they never clean it...
The cleaning process is not that complicated, besides removing the brass-ring you just use a cloth, maybe with alcohol and wipe the piston, threads and contacts off. Then slightly relube with silicone (non petroleum based) grease, if you don't care about o-rings and watertightness any other grease does it as well. Some people simply remove the o-ring from the piston, the piston then works smooth even if a little dirty, no more water protection obviously, if the light os not used in wet conditions, you don't need it.