This assumes you have a shell on the guru plug and that it can contact the internet to download the packages. Note that the default guru plug is insecure and comes with a lot of extras (samba, myqls, lighthttpd etc.) that aren't required. Fixing this is outside the scope of this tutorial.
Add a user ola for the daemon to run as:
$ adduser ola
If you intend to use USB devices, you need to add this user to the plugdev & dialout groups. Modify the lines in /etc/group:
Finally add any udev rules that you'll need. See OLA Device Specific Configuration
Change to the ola user and the start the daemon:
$ su ola $ olad -l 3