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Decide where to site the transformer, you might be able to avoid having a new circuit or socket put in for it. Then the bell wire goes between the bell, wherever you want that to be and the light up push button you've posted and the transformer. Hiding that is the most time consuming part but it's fairly easy for a decorator. I wouldn't ask a joiner fitting a door to do it though. You could avoid an electrician although some are very good at this sort of thing.
Sometimes trunking as a temporary measure and get it in the wall when you decorate.
It is a good time to do it if you're replacing the frame though, the fitter should be able to get the wire to the floor or ceiling depending on what works best.
Pretty much everyone who arrives at my house, delivery drivers in particular, seem to just thump on the door. The whizzy Arlo video doorbell has cobwebs growing all over it. I'd go for a good sturdy door knocker.