New Player, Advice Appreciated

Hi all. Myself and a friend are looking at getting into Underworlds and we're a bit stuck on where to start.

I have multiple warbands (I bought them for the minis, as smaller projects) and understand that some of them may now be unplayable - Garrek's Reavers, Magore's Fiends etc.

I'm aware we'll need the Embergard set for the board, cards and tokens, but in terms of decks and anything else what do we need to pick up?

Any advice would be great.