update flow page documentation (#190)

Author: larshp

src/user-guide/reference/flow.md

@@ -4,4 +4,17 @@ category: reference
 order: 90
 ---
 
-BETA feature, use this if you know what you are doing
+BETA FEATURE
+
+The abapGit flow page helps mirroring branches/pull requests into/from transports by doing filtered git operations. This way, it is possible to work on multiple branches in one system, or pull multiple branches into a system.
+
+:::warning
+Filtered git operations is not a real git thing, its something else than git. It is a workable compromise to work with git in a multi user system
+:::
+
+The flow page gives an overview of all features that a developer is working on across their favorite repositories.
+
+## Enabling
+
+To enable a repository to work with flow, go to the local repository settings and tick "Flow Page".
+Furthermore, developers must set their favorite repositories, so abapGit knows which parts each developer is working on.