I'm Jack with the openFDA Team. We've included extensive documentation on the website, but if you have specific questions (including example queries you've attempted just like @JanDoggen mentioned), I'd be happy to address those specifics. Otherwise check out the documentation linked below.
An example query from this endpoint: https://open.fda.gov/apis/animalandveterinary/event/example-api-queries/
The interactive chart show you what query it runs based on selected options: https://open.fda.gov/apis/animalandveterinary/event/explore-the-api-with-an-interactive-chart/
https://open.fda.gov/apis/query-parameters/ and the other pages under "Construct the Query" will teach you the syntax you'll need to build queries.
You can also just download the dataset if you need large chunks of data, but querying the API suits most needs.
Let me know if this helps or if you have any other questions.