Details of the acquisition can be found here (and are being updated as more is determined): https://wiki.guildwars.com/wiki/Silve... . Currently, it is thought that you need to have Lucky Aura (from a Lunar Fortune), be under the effects of a Birthday Cupcake, the world to have the Favour of the Gods, and be solo. Head West of of Sifhalla into Drakkar Lake, run or fight to just West of Kilroy Stonekin, then use Light of Deldrimor to spawn the boss.

I used a spirit spam build as a monk, so something similar should work for all professions. Taking your Norn title, if you have it, will give you extra maximum health.