A great help article can be [found here].(https://help.github.com/en/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent)
id_rsa.pub if there is not one already and open up Github and add it to your SSH keys in the account.
ssh-keygen -t rsa -b 4096 -C "firstname.lastname@example.org" pbcopy < ~/.ssh/id_rsa.pub
Add the copied SSH to Github SSH keys in settings.