Json-Mongodb question: who can use mysql to briefly describe what the Mongodb data structure looks like?

After reading the introduction, we only know that the Mongodb data is in the file using json. But I still don't understand. who can help me compare what the relational databases correspond to in Mongodb. I know it is not a kind of thing, but if it is all about data storage, it can explain how mysql is stored and how Mongodb is made. Thank you. Mysqljsonmongodb database

After reading the introduction, we only know that the Mongodb data is in the file using json.
But I still don't understand,
Who can help me compare what a relational database corresponds to in Mongodb.
I know it is not a kind of thing, but if it is all about data storage, it can explain how mysql is stored and how Mongodb is made.
Thank you.