What is a tailsman?

If you mean a talisman, a talisman is an item in RuneScape which, after completing the quest Rune Mysteries, allows you to create runes by having rune essence or pure essence in your inventory, mined from rune essence mines. Left click it to give you directions to the altar. Then, use the talisman on the altar, and click on the stone in the middle. Congratulations, you have made runes. Depending on which altar you went to, you will make runes of that kind.