Help in understanding the use of information in machine learning models

Hello all,

I am a complete beginner to machine learning so youll have to bear with me. I would like to understand how machine learning - in particular, collaborative filter and DNN work with information that you may get in recommendation systems. For example game recommendations, how does the model use data such as the users different games and the games data such as play time, achievements unlocked, and their reviews. The whole part of having different information linked to the games which link to a user is baffling me. How would you use this data to train a model?

Again, sorry for this question and thanks for any answers!