This is: How to replace a circuit board in a furnace
Replacing a circuit board is pretty easy if done right. But, if done wrong can be a total nightmare.
Take as many pictures of the circuit board from as many angles as possible. Now get photos of the model and serial number of the furnace itself.
Take your model number and pictures of the circuit board with you to the local air conditioning parts distributor. With the pictures they will be able to give you the exact OEM circuit board. Do not put in a universal or a different board always opt for an exact replacement even if it costs more.