README: update Getting Started, add References

README.md

@@ -11,7 +11,7 @@ The extension is licensed under [AGPL-3.0](LICENSE.txt).
 ## Requirements
 
 * PHP v7.2+
-* CiviCRM (*FIXME: Version number*)
+* CiviCRM 5.44 or later
 
 ## Installation
 
@@ -19,11 +19,19 @@ Install as a regular CiviCRM extension.
 
 ## Getting Started
 
-(* FIXME: Where would a new user navigate to get started? What changes would they see? *)
+After enabling the extension, you may want to enable the Scheduled Job (under Administration > System Settings)
+so that mailings are automatically archived after a certain number of days.
 
-## Known Issues
+Completed mailings can also be manually archived from the CiviMail screen (Scheduled and Sent Mailings).
+Click on the "more" menu associated with a mailing, then click "archive". This setting previously did not
+really do anything, except set a "is archive = yes" flag in the database, which was mostly symbolic.
 
-(* FIXME *)
+## References
+
+Previous discussion on this topic:
+
+* https://civicrm.stackexchange.com/questions/28483/best-way-to-cleanup-civimail-database-tables
+* https://forum.civicrm.org/index.php%3Ftopic=6079.0.html
 
 ## TODO