add some documentation structure

docs/guides/index.md

@@ -0,0 +1,13 @@
+---
+title: Guides
+order: 0
+sidebar_title: Start
+summary: >-
+    Guides are your one-stop-shop for reaching a certain goal.
+    You want to achieve something? The relevant guide will give you step-by-step instructions on how to do it.
+---
+
+For a complete list, see the sidebar on the left but the important guides everyone should know are the following:
+
+- [Writing Documentation](./writing-documentation.md)
+