The DJ.Studio app doesn't work on Chromebooks, we only have a Mac or Windows version.
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You can use the DJ.Studio web version on https://app.dj.studio, but that version has less functionality ( no stem separation, not streaming music, no integrations with local music libraries) and you need to make sure that you save your projects a lot via Export > Backup.
If your machine decides to clear your cookies, you will loose your projects.