I am beyond confused on how to keep my save data when I update the game. I tried to follow the instructions here but it just confused me more.
Your save data isn't in the files of the game, it's saved in a seperate folder found at C:\Users\'YourName'\AppData\LocalLow\Bayden\Monster Mystery in a file called "save.mmdata"
Because of this, you can delete the old versions of the game and play updated versions without fiddling with your save data at all >vv<
I hope that helps!