I am doing M220JS and finding it very hard to get my head around. I did M001 and found it very straight forward every concept was explained clearly. Did I miss something in between? Is there another course that could bridge the gap?
For context, I am familiar with front-end development and have mid-level working knowledge of JS, I am not an expert by any means, but I am not a total beginner. It is however my first real venture into back-end tech.
Hello @Hal_S
great that you keep going! In case you saw some difficulties with M001 I suggest to identify the hotspots which you think you can improve. Based on the provided corrections you get the correct direction. Often you’ll get links for further reading, also you can check out the MongoDB Docs you will find an immense amount of information.
In case you want to get your head free, M100 MongoDB coming from SQL – my personal translation here 
M220* are intermediate level, that still might fit when you have a frontend background but it would not be my recommendation.
What you generally want to take depends on you interest there are learning pathes - I assume the dev path is what you have in mind. In case you want to archive the developer certification you may first have a glance on the study guide to get feeling for the expected content. Even when M100 is not in the path I’d recommend, for you personally, to take it. That might build an easy bridge to the new terminologies.
Regards,
Michael