Navigate to the Cambridge multitracks library↗ and find a project that it is reasonable for you to mix.

Import into ProTools

Use the ProTools project import dialog to import audio tracks:

If prompted to choose a destination folder, click Open:

For audio import options, select "New Track"

Now that you've imported files into ProTools, follow the advice on the ProTools - Gain Staging Basics - Module Intro to correctly organize your tracks.