No pages when I install a new theme

for some reason every time I install a new theme– my pages don’t show up– well they’re there but when I click on them– the page is blank.

The only theme that works is the one that install when I first started using WordPress

please help!

https://www.prototypemama.com– this is a theme that I just installed go click on one of my post or pages and see what I’m talking about please