See Garagedoor. If that suits your needs you can just install it from the Marketplace (once you update to 3.2). Until then you can go to Developer Tools → Widgets, click the + to create a new widget and paste the YAML from that post to the code side. Save.
Now go to your Item(s), “Add Metadata” and “Default List Item Widget”. Select the widget you just create from the list and set the properties as desired. Now everywhere that Item appears in a card it will use that widget. If you modify the code of the widget back under Developer Tools → Widgets, it will automatically update it on every Item that is configured to use that widget.
If you only have the one widget, you can use that as an example. Essentially what you want is an oh-list-item with a command action to send ON to your Item.
One thing to note with the above widget, it combines the state of the garage door (i.e. OPEN/CLOSED) with the ability to send the ON command to the different Item that triggers the opener. So you can put it on one of those two Items and set the visibility of the other one to false so only the one Item with this widget gets shown in the cards.