Learn Android MVVM architecture components with kotlin

After searching about android architecture components I realized that MVVM is better than other architectures at some points so I started to learn MVVM and I'm using Kotlin language but the problem is when I search for tutorials to start learning I found many components like RxJava, RxAndroid, Dagger2, Room, Lifecycle and etc. but they don't say why they are using them and why they choose some specific components. i will show you some examples :

1- Android MVVM with Dagger2, Retrofit, RxJava

2- Android MVVM with Dagger2, Retrofit, RxAndroid

3- Android app with MVVM dagger2 RxJava Livedata and Room

My questions are :

1- How should I decide to choose some of these components and work with them?

2- How should I know that I need to use some of them together(for example Livedata and RxJava)?

This is really confusing for me and I don't know how to start.