Constructing a QQL query is easy. Before getting started with query creation, we recommend that you familiarize yourself with the components of a QQL query and the syntax that you must follow while building a query. You should also take a look at all the available search tokens for the Qualys modules in your subscription.
See Tokens for all Qualys modules
Here are a few topics that will help you get up to speed with creating QQL queries:
How to enter dates in your queries
Full Text Search on certain fields