This document provides instructions for modifying a computer's hosts file: 1. Turn off internet access and locate the hosts file, which varies by operating system, but is typically in C:\WINDOWS\SYSTEM32\DRIVERS\ETC. 2. Make a backup copy of the existing hosts file content by copying and pasting anything after a certain line into a new text file. 3. Rename the existing hosts file to hostsbackup in preparation for modifying the original hosts file. The document then provides tips to address permission errors that may occur when trying to modify the hosts file.