Step 1: Prepare your jars and scale the fish
Scale the fish. You take a knife and scrape backwards scraping all the scales off. There's a special tool to do this but I've never tried it and after scaling as many fish as I have I'm tempted to buy one. I've viewed it in use online and it looks like it would be quicker and easier on the fingers. Don't worry if you don't get every single scale off, you just need the majority gone.