Cheetah v6.4.1 Reference Guide is distributed and controlled as part of Cheetah v6.4.1 software. This guide is available online for your convenience. See the guide by following this link:

https://neuralynx.com/cheetah-ref-guide/

Please note that this guide may not match the version of Cheetah Software you are using, if in doubt please reference the version that was distributed with your software.