Can't help you with building it from scratch, but regarding the project obtained from Visionaire, just open it in the Studio and hit Build->Build bundles/APKs...
Be sure you have the latest versions of plugins in Tools/SDK Manager (select Android SDK).
Before you do that tho, you can:
Rename the game in string.xml (in res/values)
Rename the package in AndroidManifest.xml and build.gradle(app)
Change the icon by right-click on res/drawable and selecting New/Image Asset.
If you want to publish on google console though, it gets even more complicated. I also think they support only app bundles now, not apk anymore (at least for games larger than a certain size).