if you set your project to private no one will see it in the itch.io searches, only those that have the link to your project page will be able to go to your page and play/ download your game. When uploading a file to itch for people to download execute, they are running from the execution file (created when create application in the GM IDE) the only way for them to get your assets is if you upload the whole source code.(an exported gmx file) Only yoyo will require your source code,( exported gmfile, ask them how) and I’m sure your assets will be quite safe with them.:) as long as they have that they will see it and judge it, for others to see it, play it and rate it, you will need to either provide the link to your game page if setting to private, or don’t set it to private, and submit as normal buy clicking the ‘submit’ game on the jam page. :)