To lock the door from the outside to lock the slide lock from the outside you need to install a lock handle with the spindle inserted into the square hole next to the operating lever.
How to install garage door bolt lock.
To install the kit on your garage door you can follow these easy steps below.
If money is an issue as these days it often times is you can perform the installation yourself.
Once installed turn the handle 90 degrees to lock the slide lock.
Secure the lock to the door and put marks where you will drill the holes.
This will turn the operating lever and extend the bolt into the locked position.