In addition to the two inlet wires, install the bedside dual control lights, and then lead two lamp

An inlet live wire is connected to the L end of switch 1, the control wire down of the lamp head is connected to the L end of switch 2, the L1 of switch 1 is connected to L1 of switch 2, and the L2 of switch 1 is connected to L2 of switch 2

One end is connected to the main power live wire, the other end is connected to the main power neutral line, and the other two contacts of the switch are connected to the contacts of the other switch.

The blue line is connected to the midpoint of the dual control switch, the red line is connected to the A line (3 wires are divided into ABC bar), the other end of the A line is connected to the midpoint of the dual control, and the BC is connected to the 1 and 3 of the dual control respectively

Single-open and dual-control:

From putting two wires at the entrance to this single-opening and dual-control; >>>More

You are non-standard wiring, you can't see it. The line of fire enters the middle head, and the other two are connected to the other two heads.