Hey like the other truck I was wondering if there is a certain entity for a timer with a beginning and an end or if that is just a plugin? I understand there are textures for it and such but yeah.
EDIT: I wouldn't happen to be trigger_counter would it?
trigger_counter counts how many times it's been triggered, it's a part of the setup. So lets name it 'counter'.
The other part can be e.g. a func_train (with 2 path_corners) that needs exactly 1 second to get from one path_corner to the other. Lets call it 'train'.
Then in the properties of both of the path_corners you set the Fire on pass to 'counter'.
Now you make a button that triggers 'train' (this is the button that starts the timer).
Now in the trigger_counter's properties set the Count before activation to the desired number of seconds and set the target to whatever you want to happen when the timer reaches 0.
If you want your timer to be visible, there are some ways you can do it but I'm in school right now so I'm a little short on time. So maybe later.