Amend help archive page

Author: PhilReedData

_data/sidebars/userguide.yml

@@ -159,7 +159,7 @@ subitems:
     title: Archives
     subitems:
       - title: Archived help and guidelines
-        url: /help/
+        url: /help/archived
       - title: Data and model annotation
         subitems:
          - title: Minimum metadata guidelines for SEEK

help/index.md help/archived.mdhelp/index.md renamed to help/archived.md

@@ -1,5 +1,7 @@
 ---
 title: FAIRDOM-SEEK User Guide
+redirect_from:
+  - /help
 ---
 
 The FAIRDOM-SEEK user guide is written for users of any FAIRDOM-SEEK instance. The pages are organised by sections on the left. You can also search at the top-right of any page.
@@ -18,6 +20,18 @@ Therefore, some functionality described in this general user guide might not be
 Please contact your local instance admin for more information.
 " %}
 
+## Archived help pages 
+
+All other pages have been [archived](/help/archived) and may not provide current information. 
+They are organised into sections for data and model annotations, controlled vocabularies and JERM.
+
+## Contributing
+
+There are many ways in which you can contribute to the SEEK software, these documents or our [FAIRDOM](https://fair-dom.org) project.
+
+If you are interested in contributing please visit our [Contributors guide](/tech/contributing).
+
+
 <!-- THE FOLLOWING IS REPLACED BY THE SIDEBAR:
 
 ## Profile