Measure window opening to determine leg and jamb measurements.
Using 5 1/4 MDF, cut jambs and legs to frame size with a hacksaw. Be sure to measure from the cut edge to make the box square.
Custom cut the number of jamb legs needed to create the desired number of shelves. These will be parallel to the frame legs.
Break down the 5-1/4 MDF to 4-9/16 with a table saw. Make sure all jamb legs are the same width.
Use a router to round each edge of the jamb legs to create a smooth polished edge.
Measure the piece of stained glass to build the frame inside the shelving unit.
Use 2-1/2" drywall screws to attach all four sides of the frame and the legs to the jamb, making sure to pre-drill each hole before screwing. Once everything is in place, insert the frame into the opening of the window.
Using shims, make the framing level, and secure to the wall using a framing nailer with 2" nails.
Once level, place the board glued against the inside of the MDF where the shelves will go.
Drill the desired number of holes and the desired width, allowing you to create floating adjustable shelves.
Measure the length of the shelves and cut each shelf to size with a hacksaw.
Cut each shelf down with the table saw to mimic the width of the jamb legs and route each end of the shelf for a smooth, polished look.
Install each shelf at the desired level.
For the stained glass area, add a stopper, using 1/4 round cut to the size of the window frame. Cut each individual piece with a hacksaw.
Find the depth where the stained glass will sit.
Attach one side of the 1/4 round bumper with the finish nailer.
When you have installed all four pieces, carefully insert the stained glass into the area. Place the other side of the stopper on the back of the stained glass window to hold it in place.
Remove all the shelves to paint and paint the desired color.
Add some trim around the edge of the window and reinstall the shelves.