With all due respect, you are starting a project, yet I am not sure you know exactly what is involved. I you have not already done so, I suggest that you study the manual for installation of the Lewmar 700:
manual for Lewmar 700 Windlass.
There are going to be lots of items you will need--including epoxy (Which needs two parts to catalyze). The epoxy is to seal the core around the holes you drill in the deck, one of which is large. (3" diameter) The core will have to be cut back and the area filled with thickened epoxy. West Systems has already thickened epoxy : 6/10 epoxy.
You are going to need a good crimper for the #8 wire, and probably second crimper for 10/12, 14/16 and 18/22 AWG wire. You will need terminals. Wire needs to be color coded: positive is red and negative is black or yellow.. You will need adhesive shrink wrap. All positive terminals or bare terminals have to be covered.
Do you have the correct size hole saw and a powerful enough drill?
You need to place the first 50 amp breaker within 7" of battery or primary busbar. I have always put in second 50 amp breaker near the helm, so that is where you can turn the power on from the helm. (I put it on the front forward bulkhead under the galley, just under the top, well outboard, so the helmsman can easily reach it from the helm seat.
You may need terminal posts when the smaller wire from the windlass connects to the #8 wire you are running from the batteries.
When buying wire and terminal fittings get marine grade (which means that they are copper tin plated, that there is an adhesive shrink wrap sleeve over the wire.
There may be a contractor or there may just be a switch.
I use fender washers to back the windlass, or a custom made plate of aluminum ( if you have a source for 1/4" aluminum plate, you can drill out the holes).
You probably will want to grind off the nonskid where you mount the windlass. You will need a good grinder (I use a 4" angle grinder with a sanding backing plate) and then a sealant (4000) when installed.
The charging of batteries is a whole other topic. The boat should have a 1/2/all / off switch. For years boaters combined (All) the batteries when running after starting and then went to ! or 2 for house use after the engine stops. In recent years most use voltage sensitive relays, to combine the batteries.