First you should save these users as a cohort. Then you have some options:

You can use that cohort to analyse these users in detail in Amplitude. This alone can bring a lot of interesting insights. I’d suggest creating user segments, one for users in this cohort, and one for users who are NOT in this cohort. This allows you to directly explore how these users differ from your other users.

If you want to explore what individual users have been doing, you can first create an event segmentation chart for that cohort. Then you can click on any data point (individual day, hour etc) → View user streams → Click on the user ids to open the page for that individual user.

From the cohort details page you can Export CSV. This gives you a file that has the user ids, along with other user property values for these users.

Thanks so much for your answer. This is perfect @MikkoKarvonen 

I didn’t see it was possible to click on a any graph data point