Cut your 1-by-1/4 inch lumber to make the size of frame you want. Put the top and bottom piece down first, then lay the two sides on top of these.
Staple the pieces together by placing three staples on top edge and three staples from the side. Do not staple the front of your frame, as this may stick out and distort the fabric when you are finished.
Stretch the fabric tightly across the frame, wrapping each edge of fabric under to form a hem for stability. Fold the fabric onto the back of the frame as you would wrap a present. Staple the fabric to the back of the frame, always keeping the fabric taut as you work.
Paint the back side the fabric using white latex house paint. Follow the design of the fabric as you paint. The parts you do not paint will allow the light to shine through, so leave plenty of fabric unpainted to form a well-lighted sculpture.
String your Christmas lights in a zigzag pattern from the top to the bottom of the inside of your frame. Do not staple them on the back, as this will make your panel difficult to hang. Leave plenty of cord at the end so you can plug your art in when it is installed.
Install your panel by hanging it like a picture, resting the top frame on a nail. Heavier pieces will need two nails. Plug your lighted wall sculpture into an outlet, and your project is complete.