The garage has no windows or doors
You press the button on the garage door remote...
You use the button on your remote, or if there is a keypad you can enter a keypad code and up it goes. Without a remote of some sort, there isn't a way beyond smashing the door in and that's highly unadvisable!
pull molding off the right and left side of door take flat bar in and poop the roller out of the track at the bottom of the door then do the other side just push it in after that and go in fix the door back up before you raze it up. good luck
You get a long semi sturdy but thin piece of flat metal or rod about three feet long, bend or cut a hook onto the end, go to the center of the door and hope there is a rope with a knot or a handle hanging from the release that allows the door to come loose from the chain that drives the door. there almost always is one... slip the tool above the door and try to feel for the rope, grab it with the tool and pull hard.. it will release if done properly and then just lift the door open by hand.
Did you try Open sesame? Kidding. I assume you don't have the remote, and there's no keypad on the outside wall? Or some older ones had just a key slot? No? I've heard that some locksmiths or garage door pros have a universal transmitter. Which is like a master key for AGD transmitters. Whether it's true or not, I don't know. I've never needed one. But the theory is sound. I can't think of any other way, without seeing it, other than cutting through the door carefully and repairing it. If you can reach the release cord somehow, that would work too. Good luck.