The colour code bands from left to right are blue,grey,orange for 6,8 and three zeros in Ohms or 68K Ohms. This is normally abbreviated to 68K. The tolerance band is gold for +/-5%. A 0.5 Watt power rating is higher than required in this circuit but the higher power makes the resistor physically larger and so it is easier to handle in the terminal block, and reading the bands is also easier.
Two alternative values are supplied in the kit for R3 and R4. 47K will make the lights flash faster and 100K will make them flash slower. Using different values for R3 and R4 will make the lights flash with a shorter duration on the side with a lower resistance value.
