If you are uncertain what is mean by "AviSys data folder", consider this image.
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In AviSys, click on "File" in the menu bar, and you will see a similar drop-down. At the very top will be a list of your AviSys data sets. You may well have only one data set, but it is possible to have many. In the example I'm showing here, I have four. My main data set is named "KENT". The blue checkmark to the left of the name "KENT" shows that it is the data set that I currently have open. The currently open data set name also appears at all times in the title bar at the top of the window. "KENT" is also my startup data set, the one that automatically opens when AviSys starts up.
But I also have three other data sets that I use occasionally. One that I call NOCOUNT is for recording a few observations that I want to remember but consider uncountable. I also have separate data sets for Odonata and Butterfly sightings.
Now, if you open your AVI6 folder (the "main AviSys folder") in Windows File Explorer, you'll see something like this:
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Notice that the AVI6 folder contains one folder for each of the AviSys data sets. These folders are your AviSys data folders. They are always directly under the AVI6 folder.
The main AviSys folder, AVI6, contains programs and other files that are needed for the overall operation of AviSys, but does not contain any personal sighting data. All of your personal sightings are recorded in an AviSys data folder.