Since I've been thanked in advance I can't screw this up.
You have to be careful of the spines. A poke with one is painful but it is a long way from your heart
Grab the fish between your thumb and third finger behind the spines. Now you can handle the fish.
The head of a cat is prominent. On the side of the fish the skull bone will protrude . On the fleshy part cut through the skin around the fish at the edge of the skull except below the protruding bone just cut straight across.
Use a pair of pliers and pull the skin off.They make a special plier for catfish but plain pliers work OK.
Cut off head and proceed like any other fish.
Some people hang the fish by its lip to skin it.
Some catfish are so large you can't grab them with one hand.I hope you catch that one.
Best of luck.