Add some info about the training instance

content/en/users/dev-env/notebooks/_index.md

@@ -86,3 +86,13 @@ EGI currently operates community instances for:
   [EOSC-Pillar](https://eosc-pillar.d4science.org/). Check with
   [D4Science support](https://www.d4science.org/contact-us) for more
   information.
+
+### Traning instance
+
+EGI can provide a custom and temporary instance of the Notebooks service for
+training events, if you have a specific event where you would like to use EGI
+Notebooks as platform for your training, [let us know](/support/).
+
+{{% alert title="Note" color="warning" %}}This instance may not use the same
+software version as in production and may not be always available, as it is
+typically configured only for specific training events. {{% /alert %}}