Transfer the app to an Android device
On the computer
In the Build menu, click save .apk to my computer
Now, AppInventor will build the app installation file:
And at the end will ask us to save the file to a computer.
Once we have saved, we will send ourselves the file by email.
On the phone
We will allow the installation of applications from an unknown source on the phone:
Settings -> Security -> Enable the installation of applications from unknown sources
We will enter the email we sent ourselves on the device and click on the attached apk file.
Click Install and the application is ready to use!