Tidy install.md

Author: stevepiercy

plone.app.dexterity/install.md

@@ -1,29 +1,21 @@
 ---
 myst:
   html_meta:
-    "description": ""
-    "property=og:description": ""
-    "property=og:title": ""
-    "keywords": ""
+    "description": "How to install Dexterity for Plone content types"
+    "property=og:description": "How to install Dexterity for Plone content types"
+    "property=og:title": "How to install Dexterity for Plone content types"
+    "keywords": "Plone, Install, Dexterity, content types"
 ---
 
-# Installing Dexterity
+# Install Dexterity
 
-How to install Dexterity and use it in your project.
+This chapter describes how to install Dexterity and use it in your project.
 
 ```{note}
-Dexterity is an **already installed part of Plone 5.x**, no action is needed here.
+Dexterity is already installed as part of Plone 5.x and later.
+No further action is needed for these versions.
 ```
 
-## Installing Dexterity on Plone 4.3
+## Install Dexterity on Plone 4.3
 
-Dexterity is included with Plone 4.3, but must be activated via the "Add-ons" configlet in site setup.
-
-```{important}
-If you installed Dexterity on a Plone site that you upgraded to Plone 4.3, you must include the relations extra `plone.app.dexterity [relations]`.
-Otherwise your site will have a broken intid utility.
-```
-
-Dexterity is distributed as a number of eggs, published on [PyPI](https://pypi.org).
-The [plone.app.dexterity](https://pypi.org/project/plone.app.dexterity/) egg pulls in all the required dependencies and should get you up and running.
-This how-to explains what you need to do to use Dexterity in a standard Plone buildout.
+See [Installing Dexterity](https://4.docs.plone.org/external/plone.app.dexterity/docs/install.html).