1. Create a SSH key

$ ssh-keygen
$ cd ./.ssh
$ ps -e | grep [s]sh-agent
$ cd ..
$ ssh-add ~/.ssh/your_id
$ ssh-add -l
$ cat ~/.ssh/your_id.pub
then, copy the whole code

2. Add SSH key to your github Account

Open Settings > SSH and GPG Keys

3. Test the connectivity

ssh -T git@github.com

4. Clone one of your Github Repository

Make sure to use SSH when clone. For example :
$ git clone git@github.com:vl3k0/vl3k0.github.io.git

5. Push your Local Repository to Github

$ cd ./your-local-repository
$ git init
$ git remote add origin git@github.com/username/repository
$ git add .
$ git commit -m “Your Commit Text”
$ git pull git@github.com/username/repository
$ git pull origin master
$ git push -u origin master –force