New pages with the same theme template update together when changes are made to one not the other

[Sarah122]

When adding a new page, I'm prompted to select a Theme Template. Right now, my only options are "default page" or "contact". I find now every time I add a new page and select one of these theme templates, any new page with the same theme template is synced. So for example, when I make changes on page page, I find the exact same changes reflected on the other page with the same theme template.

Can someone please help me understand how to un-sync the changes made on new pages so that I can create unique pages? Thank you!