Fix guide on jupyter in own browser

Sometimes jupyter only prints one URL which makes the instruction in
step 6 wrong. Added a more specific instruction and what to do if the
wrong URL is printed by jupyter.

HPC_Python_Guide.md

@@ -169,10 +169,14 @@ Credit goes to Niels Jeppesen who figured all this out.
    where `<USERNAME>` is your DTU user name and `<HOSTNAME>` is the hostname you found in step 3.
    This should prompt you for your DTU password, _**and then NOTHING SHOULD HAPPEN**_.
 
-6. Open your browser and enter the bottom URL printed in step 5.
-   (e.g. `http://127.0.0.1:44000/lab?token=401720c25a3e9411a5f28d9015591b19a9032fc90989ffa0`)
+6. Open your browser and enter the URL printed in step 5 that starts with `127.0.0.1`
+   (e.g. `http://127.0.0.1:44000/lab?token=401720c25a3e9411a5f28d9015591b19a9032fc90989ffa0`).
    This should open the Jupyter interface. Any commands you run will be executed on the HPC
-   cluster.
+   cluster. 
+   
+   **NOTE:** If no URL beginning with `127.0.0.1` was printed in step 5, change the first part
+   manually to `127.0.0.1` before entering it in your browser. In the example from step 5, you
+   would change `n-62-20-9` to `12.0.0.1`.
 
 If you close your browser, you can reconnnect by entering the URL again.
 If you lose your internet connection, you can reconnect by repeating steps 5 and 6.