I used 0.5 mm thick frosted acrylic sheet. You may need to trim the window panels slightly after offering them up, in ordr to get the best fit. You can use thicker sheet but will have to trim the front and rear panels slightly as these butt up to the side panel.
First slide the side window panel down the inside of the side elevation until it reaches the floor, as shown below.
Attach a piece of double-sided tape to the side of the front glazing panel. Make sure it is the side that will be facing out, as shown above. Try to place the tape under the cut-out section only, as any further left will result in the tape being visible through the windows.
Attach a piece of double-sided tape to both ends of the underside of the roof. Cut the tape so it extends a little over the raised section, as shown above.
Press down carefully for a good fit.