The limit of only being able to save three projects at a time was removed from Pro Tools | First in April 2019. It’s now possible to save as many projects as you like locally on your computer. 

You can get the latest version of Pro Tools | First from Avid’s website. Go to 'My Account' > 'My Products' > 'My Products & Subscriptions' > 'Product Details and Download Links' - 'Show'. 

If you cannot see Pro Tools | First in your Avid Account, you can redeem the software alongside the Creative Pack Plug-ins from the "My Software" section of your Focusrite account if you have a qualifying product. More information about this can be found here.

Once you have updated/installed, you can save a project locally by un-ticking the ‘Backup to Cloud’ option for the project in the Pro Tools | First projects dashboard:

There is still a limit of three cloud projects.