It sounds good that you found a good source to make yourself aware of mobile app development. However, if you want my advice as a beginner, I would recommend you try developing social media applications. These applications don't only have an outstanding resell value, but you can also make yourself aware of user management.
In this regard, if you need a detailed tutorial, then you must read this
guide to develop a social media app, and it will tell you everything you need to learn before starting this development. I think using React.js would be beneficial, and you must try BaaS platforms. Yes, the use of cloud computing platforms is rapidly increasing, and you will get several high-paying job opportunities with this approach.
Best of luck!