You might take a look at this tutorial from @KidSquid that describes his setup for controlling two garage doors and an automated gate. Search for the word momentary to see how he implemented a momentary contact switch (like a pushbutton that is only ON while pressed.) He used the expire binding with a Switch item along with the autoupdate option set to false to achieve this.
There is also the following post asking for help with the implementation of a pushbutton:
