Thanks for that, but I'm still confused! specifically the instructions:
"To enable the console add -console to your launch options in properties in steam
play games TO ADD MORE THAN 1 COMMAND TO LAUNCH OPTIONS CHANGE THE PREFIX - TO + ON
THE SECOND/THIRD/FORTH EXT.
In gameplay press the ` button (under the esc button) to bring up the console
To enable the cheats first you must enter sv_cheats 1 into the console
Enter these codes into the console in get desired effect"
There are no properties as far as I can see in steam

so I am unable to add -console!