Clarify limits of the guide

README.md

 # How to work with JupyterLab everywhere
 
-_This will walk you through the complete setup of JupyterLab and one or more
-scientific Python computing environments on your local computer or on a remote 
-machine.  Currently, only Linux / Unix and MacOSX is covered._
+_This guide **will** walk you through the complete setup of JupyterLab and
+one or more scientific Python computing environments on your local computer
+or on a remote machine.  Currently, only Linux / Unix and MacOSX is covered._
+
+_This guild **will not** explain how to use the shell, how to connect to 
+remote machines via SSH, or how to make sure you have acces to the relevant
+networks, e.g., via VPN._
 
 
 ## Install the base environment and JupyterLab