I’d take a look at this code by Noah here ( CookieTech )
Before commands are executed in the mainmodule you would likely have to call the CheckIfAllowed(Player) function and once commands are run call the Record_Time(Player) function. Make sure to edit the variable Min_Seconds to how long you want the cooldown to last.
It would take awhile to add it to all the commands so I wont do it for you.