This document provides instructions for connecting to an Amazon EC2 Linux instance using a key pair. It outlines downloading the key pair file when creating the instance, modifying permissions on the key pair file, and using the ssh command with the -i option to specify the key pair file when connecting to the instance by public IP or private IP. The key steps are: 1) create a key pair when launching the instance, 2) copy the private key file, 3) modify permissions on the private key file, 4) connect to the instance via ssh specifying the private key file.