This is the shortest honest path from ZIP to a working site. If you like skipping steps, you will enjoy troubleshooting later.
Install SP Page Builder from JoomShaper first. Confirm Joomla 4, 5, or 6 with PHP 8.1 or newer. Log in as a Super User. Take a full site and database backup. If you plan to turn Media patches On, remember that switch is a CODE HACK that changes SP Page Builder files on disk.
Open System → Install → Extensions and upload the RCA SPPB Compat ZIP. Enable System - RCA SPPB Compat if Joomla did not enable it automatically. Read the post-install message. It tells you to open plugin settings and set every switch before you assume anything works.
Open System → Plugins → System - RCA SPPB Compat. Under Feature switches, decide what this site needs, then Save. Most Joomla 6 sites that use the SPPB Media Manager leave Media patches, Article checkout, Options field path, and License update sync On and leave Diagnostics Off. Turn Media patches Off if you refuse disk changes.
Clear Joomla cache under System → Clear Cache. If Media patches is On, open SP Page Builder Media Manager and confirm both the SPPB files root and the normal Joomla images root are reachable. If Article checkout is On, edit an article in SP Page Builder, return to the normal article screen, and confirm Save and Save and Close are present.
If you still have RCA SPPB Article Checkout or RCA SPPB Config installed, confirm the Compat installer disabled them. Test the workflows you care about, then uninstall the old packages. Running the legacy plugins beside this host is not supported.