Need next button on gallery main page... too many galleries and don't wanna scroll...

I started with the Flowing_Dark theme, modified it... and the problem is
the client has tons of galleries...

But none of the themes allow you to have next button - or page 1 | 2 | 3

so that I don't have a hundred galleries on opening page...

rather limit to 10 - then next page or More Galleries - button?

thanks!!!

Jen