For a ring, you can use a wooden circle, a packing tube or even a needlepoint hoop. Make sure that the ring material is durable because this is what can make your loom durable as well.
Use a measuring tape to measure the peg placement. The number of pegs can determine the size of your finished project. This is why if you need to knit a larger item, you have to use more pegs. With a pen or pencil, mark the place where you wish to place each peg.
Make sure that you secure the pegs to the ring. For this task, you need a hammer or duct tape. For a wooden ring, you can use the hammer. For cardboard or plastic materials, you need tape.
Before beginning your project, test the strength of your knitting loom. You can do this by knitting a small piece of material. Check if the pegs are staying in place.