[ubuntu] app installation on BQ ubuntu tablet

Hi Community:

I bought a nice BQ Ubuntu tablet... and they delivered it to the US.

How do I install apps? I want to install Gmail, Firefox, and VLC, and flac support.

When I go to the "Ubuntu App Store" there isn't a button to install anything!

How do I get these installed?

Also, Is there a way to use synaptic on the tablet?

Thanks!
Old Jimma from the Old Country