How do I turn my enchanted slayer gem into a ring????

How do I turn my enchanted slayer gem into a ring????

 

You need to unlock it with your slayer points, then go to a furnace with a ring mould, gold bar and your gem. Craft it.

Requires 75 crafting.

Adding on to above, ring is 300 points to unlock.

And one last note is to have the ability of point systems via slayer, you need to have completed the quest Smoking Kills (which according to your adventures log, TC, you haven't.)

And on a further point, if you don't have 75 crafting yourself, you can find someone who does and also have the ability unlocked to assist you (Both players must have ability unlocked)