Hi,
Data hooks are typically used to manipulate data before or after saving to the collection. For example, changing to fields to all CAPs or, or calculating a sum, etc. I would recommend reading the article About Data Hooks .
You can also get some “hands-on” experience by playing with the tutorial How to Use Data Hooks . Trying it out yourself in the editor will help you understand the what and how of data hooks.
Have fun,
Yisrael