[2020 update] I made a guide on installing Exagear: https://insrt.uk/post/exagear-install
If you need any help feel free to contact me: https://insrt.uk

Exagear is dead.
:(

[all commands and additional help links below]
!! note, this requires you to either activate the exagear trial or buy an exagear license !!
To learn how to do either of these see below:

Install Trial: https://docs.eltechs.com/install-and-configure-exagear-desktop/how-to-install-exagear-desktop-trial
Activate: https://docs.eltechs.com/install-and-configure-exagear-desktop/activation-of-exagear-desktop

Full guide + commands: https://insrt.uk/posts/cs16-on-raspberry-pi-3.html

=== additional links ===

SteamCMD guide: https://developer.valvesoftware.com/wiki/SteamCMD#Linux