How can I install elementary OS Loki alongside Ubuntu 16.10? I tried the ppa, but keep getting the error message: E: Unable to locate package elementary-desktop.
Just download iso from elementary OS and make bootable USB or CD. Boot your computer from USB/CD and choose install elementary OS. The you'll have an option to install elementary OS alongside other systems. Choose it and the you'll have a simple hard drive manager to make some space for elementary OS.
Finally, follow installing instructions on screen. :)