Not really hard. Just soak the bolts in PB Blaster for a few days to start with. Depending upon the lift height you will need to get new bolts to replace the ones you are taking out. Lowes and other hardware stores stock these. You will need to determine if there is a radiator drop, transfer case linkage adapter, steering block, and gas filler hose extender. You should be able to search online and find the instructions for installing a body lift and then work backwards.
Here are the instructions that I recently used to remove a 3" body lift.