Kirk,
There are two manufacturers of the NanoVNA-F: Deepelec (BH5HNU) and Sysjoint. If you have a genuine Deepelec you can get the latest firmware and a Quick Start Guide at this link...
This group is great for general NanoVNA discussion. There is a dedicated group for the NanoVNA-F and you will find a lot of good information there. In particular the menu map.
/g/nanovna-fIf you are just starting out you will find the Absolute Beginners Guide to the NanoVNA very useful reading. Ignore the section on upgrading firmware because the NanoVNA-F uses a different method.
Roger