Samsung Galaxy S9 motherboard swap

I have purchased a fully working Samsung Galaxy S9 and will be swapping the motherboard from the old phone to new phone. ( will be cleaning the original motherboard from water damaged phone using some 99.9 isopropyl alcohol prior to swap and hope for the best, I believe the motherboard is OK and just the screen on the original phone was damaged.)

What I need to know now is on the new phone prior to swap, do i need to go through setting up the new phone prior to motherboard swap or do I swap before doing phone setup or does it not make any difference either way?

Thanks