Yes, you have to include the entire string.
Usually, after creating your keypair you simply move it to your server (your PI in this case).
This works with this command:
ssh-copy-id -i .ssh/key_rsa.pub [email protected]
with PI-USERNAME being your username on the PI and 192.168.56.101 being the IP of your PI.
Afterwards you will be able to authenticate using public key cryptography, without entering your password.