Please: Take really good care, you're dealing with a lot of power...
We added reading lights to our standard IKEA Malm bed by cutting two holes in the bed, placing the lights inside. The power comes from the power outlet we had mounted in the sideboard some weeks ago.
Keep in mind that you are sleeping there - don't buy lights that have sharp edges. That's why we got those rounded ones.
Hidden behind the bed there are two radio receivers (cheaper than a dimmable switch) and the transformers we needed for these types of lights.
Don't forget: You might need a big hole in the front to put in the lights, but only a small hole in the back of your bed where the wires come out.
Close to the door we added a radio wall switch next to the regular switch, which is for the ceiling light. This way, we can switch off the ceiling light and turn on the reading lights at the same time
To switch off the lights we also have this tiny remote which was included.