Google Maps BDK won't load

I’ve added the Google Maps BDK to my app but I can’t get the map to load at all. I’ve put a standard but tiny Google Map Element on the page but the BDK shows me nothing.
I’ve followed the instructions that came with it but to no avail - they seem a bit out of date and don’t relate to options on my screen.
Can anyone suggest something I have to do to get it to work? I bought this app because it promised functionality I need but it won’t even let me display a map so it’s a step backward so far.