Working out the panelling of the door was a challenge. As I am working with second-hand and donated wood, I had to work out how best to utilise what I have. The tongue and groove is 111mm wide and the width of the aperture is 446mm, which left me 22mm short. I found some batten that would fit, but it was not thick enough. I found something thick enough, but too wide. In the end, I plumped for trimming the latter to fit. I took my time and sliced the excess off with a handsaw.
I then thought about how it should look when completed; what sort of trim, etc. and how the hinges would sit.
Once I was happy with what would be the final result, I tidied away and set the panelling up in the frame.
Finally, I glued the panelling.