Go to: C:\Windows\System32\drivers\etc
Open the "hosts" file with notepad
Add the following to that file without the "":
"104.20.3.87 8chan.co
104.20.3.87 media.8chan.co"

Congratiolations, you now have 8chan.

For mac/linux type this into a terminal, enter your password when prompted:

echo "echo 104.20.3.87 8chan.co >> /etc/hosts" | sudo bash