android studio is a framework that allows you to build android apps.
it is not something to learn.
you should learn programming language like java and then learn xml, then there are many categories in the android you have to learn them like camera capture, listview, API or firebase, etc.
For creating any app like TikTok or other apps which deal with a huge amount of data, you must have a good back end as well as catchy UI. As Ahmed Mostafa said, Android Studio is an IDE that is used to create such apps. To work on this IDE, you must know about programming languages like Java/Kotlin, also XML for creating UI, selection of suitable database, you have to apply some ML algorithms like Matrix Factorisation for recommendations and some technical knowledge about your target devices.