Hey there,
I am really sorry for the delay of this reply as it is a weekend for us here.
When you purchased easyblog license, all the default theme already included into the installer, you can set which theme you would like to use from backend > Easyblog > themes.
That install theme section is for those 3rd party template club if they got created a custom theme for Easyblog, then you can use this way to install it.