I had a question about how a psyker in DH gains the various psychic powers. In the core book it says how the PC gains minor psychic powers (1/2 WP bonus per psy rating, bought with XP), but not how they gain the abilities found in the major disciplines (like biomancy or telekine). My questions are:

How do they gain these abilities, do NPCs have to teach them? And even then, what is the mechanic, is it XP cost?

Are the discipline powers treated the same as minor powers i.e. he gets 1/2 his WP bonus of powers? Can he buy new ones with XP?

Any clarification anyone can give me would be awesome, I'm at a complete dead end trying to figure this out.

You gain your first Major Power with Psy Rating 3. It's all in the talent description

Then you can gain more by purchasing the Psychic Power Talent from your Rank advancement schemes.

With further Psy Ratings (4+) You must choose whether to learn a new Discipline and gain 1 power from this, or to get a number of new powers for your existing Discipline(s) based on your WPB