updated with short instructions on mercurial

README.txt

@@ -69,3 +69,36 @@ it also creates an HTML version.
 
 By default, revision number (REV) is set to "00": make sure to increment this
 as IETF contributions are furthered.
+
+
+Version Control System (Mercurial)
+==================================
+
+Most important commands:
+
+* download repository / initialization
+  1) hg clone https://pep.foundation/dev/repos/internet-drafts/
+
+
+* Update local directories to latest repository state:
+  1) hg pull
+  2) hg update
+
+  Note: Merge handling may be required to take care of
+  (if indicated after hg update)
+
+
+* Upload local changes to repository 
+
+  Important: To avoid conflicts, _always_ update the local directories
+  to latest repository state (see commands in last bullet point)
+  _before_commit_!
+
+  1) hg commit -m "<Changelog, short description of changes>" [ <filename> ]
+  2) hg push
+
+
+More information:
+
+* https://www.mercurial-scm.org/
+* https://www.mercurial-scm.org/wiki/Tutorial