Version 1.0.45 is the latest firmware released by Hugen for his NanoVNA-H. It has a lot of features and I suggest you get used to using it before you even consider updating your firmware.
The Absolute Beginners Guide that Vladimir Lebedev posted a link to is very good reading and will get you started.
I own a RigExpert Analyzer and an MFJ-259B. They are simpler to operate but do not have all the features and capability of the NanoVNA which is also less money. If all you want to do is measure SWR of antennas the RigExpert has more features for that and has a minimal learning curve. I have an AA-55 Zoom and it works well except for the Bluetooth which has a well-known design defect that RigExpert will not fix.
Roger
Roger Need