Initially I tried to do it the way the tutorial says, where you put glue on the edge of the fabric and line up cotton crochet string along the very edge, then use your fingertips to roll the fabric over the thread, and then trim off the extra. Riiiiight. If you have 1/12th scale fingers, that might work. I couldn’t get the fabric to want to roll, and it would come unstuck after I trimmed it, so I ended up just rolling the thin strip of gluey fabric and the string between my fingers and hoping it would mostly cover the string. Most of the orange chair’s piping was done that way.
Then I tried another way. I spread a layer of glue on the edge of the fabric like before only a bit wider, then laid the string into it and folded it over. I used my fingernail to shove the thread all the way into the fold and make the fabric stick together, and then ran my fingernail back and forth along the string keeping it pushed in while the glue set. When it was stuck good, I trimmed away the excess fabric to leave just the fabric-wrapped thread. It comes out more flat than round that way, but I think it looks finer. The piping around the lower part of the orange chair, and all the piping on the black chair, was done the second way.