Russia Restricted (RR) means that Russia can not attack in its first round. It just skips it’s combat move and goes straight to non-combat.
Submerging subs means that subs that survive the first round of an attack get to “submerge” and not be shot at anymore. It remains in the same seazone, just invisible for the duration of the round. It may attack/be attacked in subsequent rounds. Its handy b/c an attacking sub is much cooler than a defending sub.
Look up “bids” in other threads for the answer to your other question.
hope this helps.