How do I apply my 2017 Calif. refund to my Calif. 2018 taxes?

[TerryA]

Near the end of the TT Calif return preparation process you are asked if you want to apply some or all of your Calif refund to 2018. Keep an eye out for it. Slow down if you need to so you don't blow past it. You probably have to answer Yes and then you'll get a screen where you indicate how much to apply.