Here is a tip about peeling the backing away from the fine paper repair tape. First of all note that the backing tape has a glossy finish and the paper tissue repair tape has a matt finish. The repair paper is much thinner (like tissue paper) than the backing tape. Once you have identified the tissue paper side of the tape just get a small length of ordinary self-adhesive tape and stick it across the end of the tape on the tissue side. Then holding the document repair tape close to the end just beyond where you have stuck the self-adhesive tape just pull on the self-adhesive tape and it should start to pull the tissue paper repair tape away from the backing tape.
Once you have separated enough of the thin paper tissue from the release liner paper, cut or tear the length to cover the torn area and burnish gently with the bone folder or similar smooth tool.