Just going out on a limb -unhook power with quick disconnect from side of house and flip breaker down in electric box to off position, open spa pack - take a pic of the one thats in there now and then make double sure they sent you the right one to begin with. If it is ,proceed to next step and start unplugging the connectors and then reinstall new board.
If this is too much for ya then A) call a local Spa hot tub tech for a service call or B) call tech support and they will walk you through it if you are comfortable doing this-dont be intimidated by the wires-its ok--we all have been there once or twice !
