Happy New Year to All

My new year didn't get off to a good start. One of my cars has a flat battery today. So I thought I'd use the Omega to give it a jump start, but I can't find the positive terminal. The negative terminal is exposed. There is a plastic thing over the positive terminal of the battery, which I unclipped but underneath that was an array of wires and fuses and I still couldn't see the terminal.
Plan B was to drive the Omega to the local motor factors and pick up a new battery. However, when realising it was closed I had no choice but to go to plan C which was to put the battery of the other car on charge. I'm just grateful the Omega's battery isn't flat. I've no idea how to change that