For the Ubuntu dCore ports there is a utility called "ppa-add" that will make use of the Ubuntu PPA archives. To add a ppa, use the below command.
If the ppa is named ppa:gwendal-lebihan-dev/cinnamon-nightly , then issue the below at a terminal:
$ sce-ppa-add ppa:gwendal-lebihan-dev/cinnamon-nightly
For more info on available PPA archives, see
https://launchpad.net/ubuntu/+ppas