link to vpn section

docs.it4i/general/accessing-the-clusters/graphical-user-interface/ood.md

@@ -8,8 +8,8 @@ For more information, see the [Open OnDemand][2] documentation.
 
 ## Access Open OnDemand
 
-To access the OOD interface, go to [https://ood.it4i.cz][3] and enter your e-INFRA CZ or IT4I credentials.
-Note that you must be connected to IT4I VPN to access the service.
+To access the OOD interface, you must be connected to [IT4I VPN][a] to access the service.
+Then go to [https://ood.it4i.cz][3] and enter your e-INFRA CZ or IT4I credentials.
 
 From the top menu bar, you can manage your files and jobs, access the cluster's shell and launch interactive apps on login nodes - Mate & XFCE desktops.
 
@@ -20,3 +20,5 @@ To restart the tutorial, click *Help* in the upper right corner.
 [1]: https://openondemand.org/
 [2]: https://osc.github.io/ood-documentation/latest/
 [3]: https://ood.it4i.cz
+
+[a]: ./vpn-access.md