How do I shrink the borders of the PP page, so I can drag clips into the workspace?

I'm not sure what you are asking ... the PP page ... um ... not sure what that is.

The Premiere workspaces are very adjustable. Here's the current main pdf manual-type documentation, with a good sized section on making workspace changes ...

https://helpx.adobe.com/pdf/premiere_pro_reference.pdf

And if you go to the application's Help menu, there are several video tutorials on modifying workspaces.

Neil