How do I reset it and use the oven again?

The only thing you can do is try and reset the electronics by killing power to it at the breaker/fuse panel on your home for one full minute then restore power. If after that the problem persists there is component failure of some sort. Follow the troubleshooting at the link provided below if you want to determine the cause of the failure.

https://www.appliancecodes.com/repairs/how-to-troubleshoot-and-fix-kenmore-range-f90-f91-f92-f93-f94-error/