What are App Store First Time Downloads?
True to its name, the “App Store First Time Downloads” metric measures the total number of devices that have downloaded your app for the very first time.
Let’s pretend you just purchased a new iPhone. After initial setup, you begin browsing the Apple App Store, looking for a few tools to make your iPhone experience even better than it already is. That’s when you discover “Amazing App #1”. It looks so good, you download it immediately. Unfortunately, after a few months, you realize that it’s not as useful as you thought it would be. So you delete it from your phone. BUT, a few months after that, you realize that you miss one or two of the features that “Amazing App #1” had. So you reinstall it on your phone. In this scenario, the first download—the one that happened right after you bought your new iPhone—would be accounted for in the “App Store First Time Downloads” metric. The second would not because Apple considers it a redownload.
To learn more, read about the “App Store Redownloads” metric.