no, the guidelines for power selection are in daemon hunters. you get 3 for free than u have to buy the rest after that.
Look on pg 121 and 128 in the Black boxes
Sorry I've read those boxes and I'm still confused. Normally a Grey Knight gets 1 power per Psy Rating. However because I took Librarian it says I do not follow those rules and can instead buy powers per deathwatch. That leaves me confused as to starting powers. Librarian specialty says I start with 3 powers chosen from specific list. So I choose 3 from that list and can buy more powers (including grey knight powers) later?
you get three chosen from grey knight, telepathy, divination and Codex Discipline. the first 3 powers are free. Any powers after these 3 free ones will cost you.
The three powers you can chose to start with are found on the chart on page 81 of DW and/or any one of the following three from the Grey Knight list, pg 128 Daemon Hunters: