How do I infuse weapons with an element?

Sorry for another question. I thought I could find the answer to this with a quick google search but I did not. Did I skip a tutorial or something by mistake? I'd like to infuse an element with my 4 star weapon to have an easier time with the harder fights.

so far weapons don't have elements and we don't know if they will have elements in the future I hope not so if you want to deal more damage then you gonna need to do augments, unlock the potential and raise then to +40