How fortuitous - I'm making lobster tonight as well, although we'll be enjoying them boiled & then served with melted lemon butter (& corn on the cob + a green salad).
I've been cooking live lobsters for over 35 years now, & it's simplicity itself. Just bring a pot large enough to hold the lobsters (or at least able to do one at a time) to a boil. No salt is necessary - the lobsters have enough salt on their own). Then just pop them in (they'll expire nearly immediately - no need to mourn) & depending on size, cook them for 15-20 minutes (which works for the normal-sized 1-1/4 to 1-1/2 pounders). Remove & allow to cool for about 5-10 minutes before splitting to eat hot; or to pick for salad or to pop into the fridge to pick out another day.
As far as what's edible - EVERYTHING!! Except for the gills, also known as "dead man's fingers", which are easy to spot as fibrous & fingerlike & nothing you'd want to eat anyway. They're not poisonous or anything, just not pleasant. But everything else in a lobster is edible - & DELICIOUS!!! We suck the meat out of the legs, & pick the meat out of the body, which, by the way is identical to lump crab meat in a well-filled lobster. (I really pity the folks that just toss the body out without realizing this.) The "green stuff" - aka "liver" or "tomalley" is also sweet & delicious, but some folks pass on it because as the liver, it will also contain any contaminants that may be present. And the "red/orange stuff", if present in a female, is the roe or eggs, & that's a true delicacy for many - myself included.
If you're still not interested in picking out the body (again - a real shame), you can pop it into the freezer & use it at a later time to make a wonderful lobster or seafood stock.