You want to use @DbLookup to retrieve a list of values, then use @Prompt to let the user choose from the list.
Questions like this always make me nervous, because this is really, really, easy stuff you’re asking about. All you have to do is read the documentation of the functions, and provide the arguments in the correct order. This is the easy part. Here’s an example of doing that.
Your description of what you want to do with the choices once the user has made them is vague, and that’s the complicated part. You haven’t described the task well enough for me to address it. Are they selecting documents from a view, or editing a document, or just viewing a document? Do you want to prompt them once for all documents, or ask them separately for each document? Can you get all the choices with a single @DbLookup, or do you have to read them from multiple sources?
If the above does not solve your problem, we need more information about what you’re doing. If you’re not sure what information to supply, the C R I S P Y document might help you.