The picture is an IKEA picture called ''ERIKSLUND'' in a black frame.
This picture was good for this project because it had some free space inside between the backside and the frontside of the glass.
Step 1: All what you Need
Shrinking hose in different sizes, double side adhesive tape, hot melt gun and a few screws.
Step 2: Remove the Backside
Step 3: Make Holes for The Switch and the Power-Cable
The Hole for the Switch can be may at a lower Edge in the Side.
A Good Place for the Hole for the Power Cable is at the Downside in the Near of The Switch-Hole.
Step 4: Solder a Piece of Wire to the LED-Bar
Make 2 Pieces of the Shrinking Hose that are approximatly 3cm Long and Put it over the Wires. Then you can Solder the Wires from the LED-Bar each with one Wire from the 2 Wire-Cable. Then Put the Shrinking Hose Pieces over the Soldered Area and Shrink it with the Flame of a Lighter.
Step 5: Attach the LED-Bar in The Frame
Cut 3 or 4 Pieces from the Tape Roll and attach the Bar with this into the Frame at the Top-Side.