The xenial ppa is not yet out so you can load up wily for now.
sudo apt-add-repository -y ppa:teejee2008/ppa
sudo apt-get update
sudo apt-get install conky-manager
https://launchpad.net/~teejee2008/+archive/ubuntu/ppa?field.series_filter=wily
or just use the gui
https://help.ubuntu.com/community/Repositories/Ubuntu#Adding_PPAs