Cannot recharge or jump to start as hornsounds;

The horn is not working , both Horn not working

The "R" was flashing and clicking from the dash at the same time. Found video that diagnosed as potential starter relay failure with testing as resolution. Auto Parts helps with a dianostic tool that says alternator is failing. I would like to test the relay using the horn relay detailed in the videos,but they appear to be different, more like a fuse. This is under the hood. I'll look again at the diagram. Maybe the relays are under dash.