Normally you would spend special attribute points from your metatype priority if you wish to increase your resonance rating from 4 to 6, not your left over karma (but left over karma is also an option, but if you use left over karma on attributes you normally only use left over karma on attributes that are very low...)
This is the order of operations:
First you spend your attribute points from the Attribute priority on Physical and Mental Attributes.
Then you get your Magic or Resonance Attribute from your Magic or Resonance priority.
Then you spend your special attribute points from the Metatype priority on Special Attributes (Edge and Magic or Resonance if you have one of them). It is the number in the parenthesis.
Then you buy gear with resources from your Resource priority. Augmentations (cyberware and bioware) might reduce your essence which might reduce your Magic or Resonance attributes (if you have one of them).
Then you spend your Left Over Karma (on for example Mental, Physical or Special attributes).
Edit. Let me give you an example.
Say you have a character with the priorities:
Attributes A (24 extra attribute points for Physical and Mental Attributes)
Magic or Resonance B (Resonance 4 Technomancer)
Skill C (28 skills and 2 skill groups)
Metatype D (Human with 3 special attribute points)
Resources E (6,000 nuyen)
You would start with Edge 2 (because of Human) and Resonance 4 (because of your Magic or Resonance priority).
From there you would spend your 3 special attribute points (because of your Human (3) metatype priority).
For example 1 of them on Edge for a total Edge rating of 3 and 2 of them on Resonance for a total Resonance rating of 6.
Then you instead use the Left Over Karma on Qualities and possible also to buy resources (at a rate of 2,000 nuyen per karma).