You will need to know a little about the pub - who uses it and what facilities it has.
NOTE: The pub does not need to be closed, for sale, or in any way under threat (although if it is, an ACV may be more urgent!). It is best to nominate pubs as soon as possible - once it closes or re-opens as a restaurant it may be too late!
An ACV nomination prevents a pub from being changed to any other use (or being demolished!) without planning permission.
Your name will not be included in any official documents, or disclosed to the owner / licensee.