Here's a few installation videos that you may find usefull...
They are predominately made in the USA but the methods are universal…
Playlist
5 Videos
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If you don’t feel like changing the batteries every six months, you can always hardwire the lock in. You just need a 12c to 6v converter, some time and patience, and some expertise, but be aware, you may affect any warranty if you unexpectantly cause damage...