FFC flatline standard line numbering
A common solution for determining cable wire numbering is to look at the connector that it is mating with see if the connector manufacturer has assigned a pin 1 to the connector. That works fine in most cases but can fall flat when beginning to use FFC that is a simple straight end to end cable.

As you can see in the image below if you define pin one at the arrow on one end of the cable then the cable routing demands that pin 1 be at the location of the other red arrow at the opposite end. So for your cable one end from the left and the other end it is from the right!!

 

(image borrowed from here)

So this becomes a careful job of systems engineering to correctly comprehend the signal routing when FFC cabling is in use.