cordova app: javascript sqlite many to many relationship

I have a Cordova project that uses SQLite to store locally some data of user. I want to create a many to many relationship, but I'm not sure how to do it.

I've read in this other question that you need to enable many to many relationships... but is that necessary in Cordova project? If so, how do I do it?

Just to be sure, how could I ask to DB, once done this if user in table U has product from table P? Is different somehow to queries in 1-1 relations?

As you can see I'm not used to working with DB, so please, asume I'm noob.