Android Question B4A .apk -> setup file

In Project/Build Configurations you set the package name (default is b4a.example).
Then you set the compile option to Release and finally you may find the new apk in the Objects folder of your project.
Use an USB cable, the B4A-Bridge program or upload your apk to a server and use a browser on the device to download the apk to it.

In addition to @udg answer (which was btw faster than me the second time )
Each App must have an Unique Packagename (Buildconfiguration). This should be the first which you should change if you start a new Project.