ok so when you are in the beta editor or old editor you see the setting button,click it then click the top button on the right and it will take you to something i dont know what it called but there will be a save button on the bottom right corner then when you click save button it will save it to your computer and when you want to upload the file you just go back to the setting button but this time click the top left corner button and then find the file you just saved and then you click on the file and it will say open in the bottom left corner and then click open then it will take you back to flipanim and then something will pop up on the top of your screen with a yes or no button CLICK THE YES BUTTON TO OPEN YOUR FILE and thats how to sue files

I hope this helps you

thx