Host a GOTV server
Read about GOTV.
Setup your GOTV server in the csgosl GOTV tab. Most relevant options can be controlled from this page.
If your server should be possible to spectate from outside your LAN you need to forward the GOTV port (default 27020) in your router to the IP address of your csgo server. See more about port forwarding on the Host public server page. For LAN only servers you don't need port forwarding.
The easiest way to connect and spectate is to select GOTV in the server browser instead of selecting the server itself. But you can also connect using the console window (see more here GOTV)
To spectate the server enter:
connect <server-ip-address>:<gotv-port>
Example:
connect 192.168.1.100:27020
If you set a password for your server use:
connect <server-ip-address>:<gotv-port>; password <your-password>
Example:
connect 192.168.1.100:27020; password 123
To allow persons to connect to your GOTV server from outside your LAN you need to give them your external IP address which you e.g. can get from whatismyip. Assuming you have properly forwarded the GOTV port in your router your friends should be be able to connect as described above using your external IP address.
To start a recording (in the console window):
tv_record "mydemo1"
To stop recording:
tv_stop
To play demo:
playdemo mydemo1
Demos are stored in Steam\SteamApps\common\Counter-Strike Global Offensive\csgo