The digital adventure books clam to have a 'combat tracker' that looks like a prebuilt encounter. I've preordered Vecna and am trying to build out the nest of the eldritch eye for my players. I don't see how these things fit together? How can I create the encounters?

Thanks!

I am curious if these are actually prebuilt encounters and you just need to run from your campaign-which will then generate the encounter with enemies and Player Characters ready to go.....

I can't seem to get a clear answer. I don't want to buy an entire adventure and find out that it isn't true. 

It's definitely a plus if I don't need to, but I'll consider it if the maps are impressive. Overall, I don't tend to use maps and prefer to just hand draw things, which makes it easier to hand wave things just a little bit https://vidmate****/  .

The maps are great, AFAICT there are no prebuilt encounters. I've just built them manually... 

Quote from bdudney >>

The digital adventure books clam to have a 'combat tracker' that looks like a prebuilt encounter

 
I think you're misinterpreting this - they are two different things and you've put them together. It does not say it has a prebuilt encounter for D&D Beyond's Encounter Tracker. The adventure has encounters, like all adventures do, and it says the monsters from the book will be unlocked for use in the Encounter Tracker tool - which is true.

There is no automatically pre-made Encounter Tool thing and this was not ever promised. You will need to create the encounters in the tool yourself.