Please join the Google Group first. You need to be a member of the group before joining the closed test.
1. Join the Google Group:
https://groups.google.com/g/cooling-tower-performance-testers
2. Join the closed test:
https://play.google.com/apps/testing/coolingtower.performance.evaluation
3. Install from Google Play:
https://play.google.com/store/apps/details?id=coolingtower.performance.evaluation