how can I set fan speed?

[mca]

I am trying to set fan speed but there is no such option. My model number is GA01334-CA

how can I enable fan speed settings on this very model? 

[Patrick_Caezza]

@mca 

Your system must be equipped with a multi-fan speed capability. If it isn't, then you can't have that option

[mca]

Patrick thanks for your reply, actually my system has fan speed options. I did a small research myself and learned about G1, G2 and G3 wiring. My nest hub only have a G wiring. Could it be the reason?