From there, take the Blue Dial to the altar at the center of the church. Interact with the altar, and you’ll be able to properly start this tricky puzzle.
Resident Evil 4 Remake: How to Solve the Church Window Puzzle
Once you interact with the altar, you’ll notice that you’re now able to “slide” the stained glass window pieces around by manipulating one color at a time. So the Green Dial lets you move the green window pieces, and so on for the blue and red pieces. You’re basically trying to slide all the window pieces into their proper places so that there are no white gaps in the display. What makes this puzzle so tricky is the fact that the colors are initially all mixed up, which makes it hard to see when one color is in the right place.
The easiest thing to do is to pick a color and try to get that color into the proper place. The Green Dial is easiest to start with since the green pieces of glass line up cleanly with the figure at the center of the display. You just need to fit the green pieces near the empty spaces around the figure’s head and upper torso. It should look like this when you’ve got it:

Next, try to move the red pieces into their proper places. One of the primary red pieces runs perfectly alongside the right side of the figure’s torso, which makes it pretty easy to spot. This is what it should look like when the red and green pieces are in the right places:

From there, it’s a simple matter of fitting all of the blue pieces into the remaining white slots. When it’s all said and done, this is what the window should look like:

With the puzzle complete, you can now enter the recently opened door and proceed through the rest of this incredible game.