How to read 5 changing lines?

I'm sorry if this has been asked dozens of times before; but what is the "correct" (for want of a better word) way to read a Hexagram with 5 changing lines?

For example: I received 40.1.2.3.4.5 > 63 recently, so do you:

A) Read the judgement of both Hex's
B) Read the unchanging line of the primary Hex
C) Read the unchanging line in the relating Hex

This has always confused me.
Say using this example (40>63) using either B or C would give opposite advice as 40.6 speaks of action but 63.6 speaks of non action

Any thoughts?