How to get practice in android development for a beginner?

Question

Java

Now I am studying development for Android and decided to take the advice of many Khabrovites for beginners.
Namely:
Set yourself a real task and start solving it.
The task is this.
There is a huge pile of documents with texts and pictures.
It is necessary to create an application that:
1. Systematizes them all, with the ability to go to any document, as well as to individual sections of the document.
2. Convenient interface
3. Search by text and voice inside the document
4. Ability to make amendments when changing documents.
Tell me where to start and how it should look, because I don’t understand how to put into practice what I learned in theory.
Thank you in advance.

Answer 1

The purpose of this post is for the post to be at the top of the feed and someone else to go to the topic

Answer 2

or maybe there are some opensource projects for android and team teams where you can enter and also take part in the development. Where can you find such projects?