File - export - select the desired format (in this jam Windows) - you will have a folder, right-click - select "add to archive" - in the archive, be sure to change the format from RAR to ZIP - go to itch, click "new project", download the game archive. BUT! I don't know what maker you have, the instruction that I gave above I tried only on RPG Maker MV, whether this instruction will work on others I really don't know.