I know, it’s been so easy this far that you’re sad the job is done. Well, get ready for the hard bit. Select a large tree that looks like the kind of place an owl would like to raise its family. Figure out where you’re going to mount the owl house. It should be a safe height off the ground to keep predators out of the box (probably at least 3 metres or so), and safe enough for you to climb up to, to hang the box. When you’ve finished the recce, climb the tree or ladder and nail the mounting perch to the tree trunk, parallel to the ground. Put the drill into the owl box, through the doorway, and screw the four 75mm screws into the back of the box, so that they are in position to be screwed into the tree. The tricky bit is to get the heavy owl box up the ladder and to rest it on the mounting cleat, and then screw the owl box to the tree, using the prepared 75mm screws. Get some help to do this, and be careful. Another option is to install the owl box in a barn (they’re not called Barn Owls for nothing) or a similar structure.
Unfortunately you can’t force owls to move into their newly constructed home, so be patient and hopeful. When you’re in the garden take a look at the box to see if there’s any evidence of residents. We’ll be holding thumbs.