What is ULD? I tried googling it, and ended up being linked to this thread lol.
Utility Land Draft. There's a semi-confusing but very detailed forum thread about it, and there's also an article about it on the websitey portion. The thing you get to when you click the big logo in the top left.
I linked to one of these things in my first post, I think? I certainly intended to.
The short of it is that, if you're booster drafting in-person, you take turns picking a land from the ULD after each pack, then you pick one more at the end of the draft. So 4 lands total.
Drafting online, it's much simpler to just take turns calling dibs on all 4 cards in a row at the end of the draft, in chat. Drafting takes long enough online.