LLBLGen Pro generate classes that map to your database tables and views, so you can use instances of those classes to read records from database tables and views, either reading one record, multiple records using some filtering criterea (which might be too complex) or reading all the recods, also you can insert new records, update existing records or delete some records.
LLBLGen Pro also generate methods that wrap calls to existing stored procedures in the database.
As have been said before there are a lot of information and examples in the docs.
Also if you have some query in mind, post it here so we can help you to perform it using LLBLGen Pro.