How do I forge? (in New players)

I know where to get the formula, and cast all the viciousness spell at the right time, but what do the commas between the numbers mean?

Those are the heating times.

A forge formula is displayed as [xx, yy].
You heat the item xx minutes.
Then cast the first spell (viciousness, accuracy, or hardness).
Then you quench the item until it is cool to the touch AND your Rough Progress Meter goes up. Some items may require an additional quench once cool to the touch.
Then you heat the item yy minutes.
Then you cast tempering.
Then you quench the item in water until it is cool to the touch, and "You feel quiet satisfaction as you gaze on your [item name here]"

thx