This is the lapsang souchong that I drink:
adagio lapsang souchong - Google Search
(if the link happens to not work, search "adagio lapsang souchong")
Those canisters will keep it reasonably fresh for a LONG time. I ordered a bunch of them in bulk over a year ago, and am about halfway through my last one. The tea is still good.
You brew it like any other loose tea. You can use a brewer or a tea-ball if you want something cheap. I use this tea brewer and love it:
Teavana® Perfect Tea Maker (32oz.) - Teavana