First you need complete the Main quest Hunting a Witch in Velen, while on you find Keira Metz. With her you complete the Main Quest Wandering in the Dark (where you also get the Eye of Nehaleni) and then ask to do the Sidequest Magic Lamp for her. Complete it to get the Sidequest An Invitation from Keira Metz
Then there are tree Sidequests (A Towerful of Mice, A Favor for a Friend and Advancement of Learning) that you need to complete. If you have a Conversion with Keira you don’t to need to be nice to her but don’t use the Conversion option with the X, if you do that the Quest will fail!
For the last Quest: For the last Quest Advancement of Learning
Here you can kill her or walk away (Quit conversion Icon), you get the Achievement after.
Remember to complete the Forefarthers’ Eve Sidequest, while you are here.