I need HELP I don't know on what to do with my 3 stitch knitted rope i made?

Depending on how long it is, you could use it has a belt or as a very thin scarf. A rug is a great idea, or you could find larger knitting needles and knit a very thick scarf. If you want you could use the rope as a decoration and hang it on your walls around your windows or a picture. You could even hang it on your christmas tree if you wanted. Hope this helped!