Hi Francisco,
First of all - congrats on the traffic!
I don’t think we have a video or tutorial that covers this specifically.
Here are some pointers at the code references which are relevant. It might make sense for you to find a JavaScript developer to help you out with this. It would be fairly easy for a developer to jump into, even if they have little experience with Wix Code.
Dropdown API - how to get the value from the dropdown elements
Dataset API - what you’re looking for would probably be most easily done by filtering the dataset using the setFilter() method
Data Query API - how to construct queries
Good luck!