[CATA Classic] Affliction rotation?

I haven’t really touched Warlock back in Cataclysm when it was current outside from a little dabble in Demonology. So I am trying to figure out if I am supposed to apply the DoTs then cast Shadow Bolt, or Drain Soul? I know Drain Soul is also used to replenish Soul Shards you use via Soulburn, but I do not know if I should be using it outside of that.

Casting Shadow Bolt seems to take too long as mobs at the level the Warlock is die pretty quickly via DoTs anyway.

Or maybe I shouldn’t be touching Affliction and go with Destro or Demo instead? But I kinda like Affliction anyway.

Thanks.

EDIT: Seems like this place is not the right place to post this?