Disconnect three thin delicate cables from the PCB. The largest cable ① comes away without too much trouble. There are small clips on either side of the connector. Use a small flathead screwdriver or flathead plastic spudger to push in the clips on the sides of the connector and slide it gently in a same plane as the PCB.

The two smaller connectors ② & ③ do not disconnect like the first - despite appearances, they pull directly away from the PCB (credit Feanor - thank you - see references in conclusion).

Place a small plastic spudger at the top of the two connectors, behind the wires and, pull gently forwards - click, off pops each connector.