Installation for Android devices uses a browser extension in Firefox.
You'll want to set the screen to stay on all the time to let the Tools run uninterrupted. If the screen turns off the Tools can't run in the background.
Depending on you tablet, you may have the option to set the screen timeout to "never" under Settings → Display → Sleep.
If you do not have this option, you can enable Settings → Developer options → Stay awake. This will keep your tablet awake while it is charging. This could be useful if your tablet does not support the "never" screen timeout.
Note: If you don't see Developer options in Settings, it may be made available by going to to Settings → About → Build number. Developer options should appear after tapping the Build Number option several times.