Replaced Control Panel Circuit Board but it doesn't light up

I can’t program the new board I replaced because it isn’t lighting up. THe old one did light up but needed to be replaced because I had the same problem of freezer OK but fridge too warm.

What did I do wrong? It says to program I need to hold in light and press - pad of freezer 3 times. I can’t do this because nothing is lighting up. As if no electricity is running the board. The rest of the fridge seems to be working.

Help!!