1st Step: kill Immortal Prelate (ONLY 1), Dancing Swords and Silver Vanguard. (NEVER BEFORE DRAW UNDATAKAH)
2nd Step: Having Undatakah, Umbra, Brann, Drakkari and Thaurisan in you hand, play Drakkari and Thaurisan, reducing the cost of the another cards.(Undatakah , Umbra  and Brann  = 9 mana)
3th: Play Umbra and Brann (in any order) and after Undatakah, the battlecry activate 2 times so always so the combo.
Your Undatakah shuffling and summon a lot of times (I don’t know exactly how many times) and your oponnent draw a cars for any time Undatakag is summoning