I’ve been setting up some salvaged laptops for a local refugee center, running linux, and wanted to open a webpage automatically with useful information when a user logs on as guest. I did some googling, but found the explanations pretty confusing and convoluted.
The solution is pretty simple, when you first figure it out. This is how I did it on my laptops, running Ubuntu 15.10. (It should also work from Ubuntu 14.04):
1. Log in as admin, and start the terminal and enter the /etc directory by typing cd /etc.
2. Create the directory guest-session, by typing sudo mkdir guest-session. Enter the dir by typing cd guest-session.
3. Typed sudo gedit auto.sh. This opens the text editor gedit with an empty document. Enter firefox «pappmaskin.no» and save the document. Close gedit.
4. Log in as guest, and the url you wrote should open.