I found out how to get to the PNGTuber+ Folder!
Go on your desktop, click on GO on the top of your screen hold down “Option” the Library folder will pop in the list, click to open window, then you just follow the the above folder links. You are going to have a lot of folders so take your time to look to find the name of the folders.
Once you get to the PNGTuberPlus folder you just have to click and drag your images in that folder.
I too am having issues with the Mic, my computer some reason isn't giving permission. The VeadoTube Mini actually was able to bypass that issue with a terminal but I don't know how to put that in for this application. Below is how you can give permission to the app to use microphone for VeadoTube Mini and it gives the terminal code I just don't know what to replace to get PNGTuber+ to work that way as well.