I followed this tutorial which cuts the jeans to the proper length and then uses a sewing machine with a zig zag pattern to create the new hem. I had to go this way instead of reusing the original hem because I needed to shorten the leg by 4 inches and would have way too much fabric at the bottom of the leg if I kept the original hem or did one of those non-sewing tricks.
I used a marker to create the lines of interest as described in the video but uh… those lines didn’t wash out. Thankfully they’re hidden unless you really go looking for them but I’d suggest a quick trip to the craft store for tailoring chalk!