6V power supply
Connect the LDR and ammeter in series with the power supply. Connect the voltmeter in parallel to the LDR.
Set the LDR up so it is 10cm from the bulb.
Switch on the lamp and record the ammeter and voltmeter readings. Switch off the lamp, then back on and repeat the readings. Repeat once more.
Move the LDR 5cm further from the bulb and take another 3 sets of readings.
Continue until you reach 40cm from the bulb.
Take the voltage reading and divide by the current to find the resistance of the LDR in each case.
The bulb being used may get hot. Care should be taken to let it cool before packing away.