Magister comes with member pages ready for Paid Memberships Pro. But you need to tell the plugin what those pages are.

Doing this is quite simple: go to Memberships | Settings and click on the “Pages” link. Then click on “Create Pages Manually” button:

In fact, the pages are already created and were installed along with the theme. Now just associate each page to its function, as in the image below:

To finish this step, just go to the bottom of the page and click on the “Save Settings” button:

For detailed information about this topic go to https://www.paidmembershipspro.com/documentation/initial-plugin-setup/step-2-setting-pages/