Not all games you create should be accessible for everyone, or you may have a prototype that you want to test that isn’t ready to go public yet. You can make your package private by checking the “Private” checkbox when you upload you package in the editor. If you want to make it public later, uncheck the checkbox when uploading a new version or change the visibility in the Edit section of the mod.io page of your mod.
If you want to play with others while your package is still private, you can either add them to the team or you preview links. To add other users to the team for your mod, open the mod.io page, go to “Edit”, then “Team” and add them using their mod.io username or email addresses.
If your players shouldn’t be part of your team, or if you don’t want to add them manually, you can use preview links: at the top of your private package’s page, there will be a notice telling you that it is not available publicly. The notice includes a link that you can share with your testers. Using the link, they can access the page of your private package. If they are logged in using their Steam account, they can subscribe and the package will be downloaded in-game. Since the preview links work through the regular browser, make sure that your players are logged in to mod.io with their Steam account! If they have already created an account using their mail address, they can link it with their Steam account by clicking on their user name in the upper right and selecting “Profile”. At the bottom of the page there’s a “Connected Accounts” section, clicking on the Steam icon will open a prompt asking them to log in with their Steam account.
Note that the preview link expires whenever you upload a new version of your package. But the subscriptions remain active, everyone who has subscribed will get the latest version automatically.