To record a demo in CS:GO, you need to open the console with the ~ key during the game, it is near the Esc key.
If the console does not open, then it probably is disabled in the settings, open the game settings and select “Yes” where “Enable Developer Console (~)”.
Then, in the console window that opens, type the command (where NAME is any name of the demo):
To stop demo recording in the console, type:
The demo file will be saved to the directory with CS:GO, for example C:\Program Files\Steam\steamapps\common\Counter-Strike Global Offensive\csgo\NAME.dem, other demos should be placed in the same directory.
To view demos, you need to open the player, for this, in the console, type:
Or press the key combination Shift + F2.
Next, in the opened player, click “Load …” and select the demo.
During viewing, you can switch between players left/right keys, CTRL – opens the map, Spacebar will switch the camera to free flight mode.