To create an APK from your app, go to the Build menu (see Figure 12.4) and select App (Save .apk to My Computer).
The build process usually takes less than 30 seconds, but it can take up to a few minutes if the build servers are busy. The build servers are different than the primary App Inventor web servers: there are a finite number of them, and they are shared among all App Inventor users.
App Inventor then downloads the file to your computer. Depending on your browser settings, either the file downloads to a preset location ...