cd ~/.ssh && ssh-keygen -t rsa
cat ~/.ssh/keyname.pub
Copy the output given as a result of the command above. It is the content of your keyname.pub file.
If you are on a Mac, you can directly copy the contents of keyname.pub by running
cat ~/.ssh/keyname.pub | pbcopy
See if ssh-agent is running
ps -e | grep [s]sh-agent
If no output is given then it means it is not running. Start the agent by running:
ssh-agent /bin/bash
Load your SSH Key with the ssh-add command
ssh-add ~/.ssh/keyname
List the loaded keys to make sure it has been added.
ssh-add -l
Go to Manage Account > Security > SSH Keys > Add Key