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First step learn your language. Pick both Java and Kotlin to learn beginners level. Play a bunch to figure out which you like better and become an expert in it. Second step select an IDE. Install Android Studio, Eclipse, and Intellij. Build those codes from step one in them. Grab a few Android demos in both languages and build and run them. Pick the one that works easiest for you. Third step learn Android. Truthfully, these steps can occur together. The important fact is you should like your tools not take someone else's choices as your own.
I would recommend you to use android studio. At first work through the android studio tutorial and get a basic understanding on the architecture. https://developer.android.com/training/basics/firstapp Depending on the focus of the app (network, showing stuff, ...) you can find lots of tutorials on YouTube.