Replacing drive belt on old troy bilt mower trimmer

I have had a troy bilt trimmer mower for some time now. Fortunately it still runs but the belt that turns the trimmer head has stretched over time. After checking on line with the model and serial number there were no listings for the machine. I had to take a deep dive into to replacing the belt and just had to wing it and figure it out as you go. Thank goodness this thing was old because it turned out to be a simple fix.