Spellhold Dungeon Level 2 Overview - Baldur's Gate 2
You can reach Level 2 of the Spellhold Dungeon by traveling south through either of the doorways on Level 1. In order to progress to Spellhold Dungeon Level 3 you will need to obtain 2 items from Level 2 and then use them to open up the Statue Head on Level 1. The 2 items that you need are Kurtulmak's Crystal Shard and The Hand of Dace, both of these locations are marked on my map overview shown above.
The main things to point out on Level 2 are the numerous high level spells that you can find throughout the area. Near one of the entrances from Level 1 you'll find an Ancient Tome which you can use to summon a couple different types of monsters. Your reward for defeating all of them will be a Simulacrum Scroll. In the library room just before Vampire Dace you'll find numerous bookshelves one of which containing the Finger of Death Scroll.
Ancient Tome: Each time you click on this tome it will summon a monster for your group to fight. The hardest enemy you'll fight is a Beholder but if you buff up before hand it shouldn't be too difficult. After defeating the Beholder click the tome one last time to receive Edventar's Gift (Ring), along with Simulacrum and Summon Fiend Scrolls.
Crystal: At this location you will find a bunch of Kobolds surrounding a large crystal. When you clear out all of the Kobolds a Kobold Shaman will spawn and you will get a quick scene with an Avatar for the crystal. The Kobold Shaman will drop a Stake which you'll need to permanently defeat the Vampire Dace on this floor -- be sure to pick that up. After the fight is over you'll also get some dialogue about taking a piece of the crystal, Kurtulmak's Crystal Shard will be added to your inventory when this happens. We need this item to progress to level 3 of Spellhold.
Vampire Dace: Here you'll find a Vampire by the name of Dace whose hand you require to progress to level 3 of Spellhold. Fight him in his Vampire form then use a Stake on his coffin to permanently kill him. The Hand of Dace will be placed into your inventory once you click on his coffin.