The example project of the tool contains characters which use graphics from https://www.patreon.com/PVGames but the character graphics aren't part of the free version of the tool. I will check why it crashes but to create a new character you can just select any unit in the list(Which are only visible if you have any graphics with characters) and then assign the equipment etc. When you are done with your changes you can save it via main menu.
Well I have the Plat Chest on PVGames Patreon so I should have the pieces for the Chracters and it was finding the other assets fine. I'm guessing Windows is bugging out it's ability to find the assets? I know I had this issue with the Philharmonik VST where it would find certain samples but not the rest, I have the files in a folder directly on the C drive due to the character limitation with directories, I'll try placing them on my D drive to see if that helps.