Linking photos within a new guide is often helpful but not required.
Before Guide Publishes
A photoset may be posted generic-named before the guide exists.
When the guide is published, you may
rename the photoset from generic to guide-based if desired.
Simultaneous Rarely utilized but works like a charm
If you have a photoset in the upload queue and have linked to these photos in a pending guide. Just type "post my photoset in upload" at the top or bottom of the guide. Admin will finish/post with the guide & change your
Generic-Based name to
Guide-Based.
After Guide Publishes
Link photos via edit after the guide is published.