I'm with the others on depth.

First boil - things to watch.
Before you even light a match, make sure that sap can get to the pans. Test each float to make sure that it will open (and close) as needed. Set your 5 gal "Oh ****" pail beside you.

It'll take a bit of monkeying to get the floats set right - I'd start with them low, let sap flow in until they shut off, then raise the depth little by little until they shut off where you want them to. All this without a fire.

Once you light, keep the fire small initially and watch to see where it boils first. You expect the back syrup section to boil first, then the other 2, then the fronts of the flues. As soon as you get a boil going, check to see those floats are opening. I can usually get my whole rig boiling before the time for the second firing (15 mins)

Once you have the whole thing boiling and you know that sap is being replenished, try to get a handle on how much wood to add, and how often. I listen to the tempo of the boiling - I can hear it start to slow down as the wood is consumed and I'm often getting ready to add the next armload just before the timer sounds. Your first several hours will be sweetening the pans, so you have lots of time to get used to the boiling and firing before you have to worry about measuring density and temperature and taking off syrup. The objective is to keep the rig boiling smoothly and get into a routine for firing that suits your evaporator. A timer does help.

Have some defoamer (or canola oil) handy for the inevitable foaming.

I'm sure others will chime in with suggestions on how to tell when the front pan is getting close, and how to take off syrup.

Good luck and enjoy.