A few questions about the "Android Market" and the general principles of app promotion?

Question

Java

Hello, I have a few questions but I can't seem to find any answers.
Tell me who is competent in this area.
I have an idea for one "Android" application that I might want to make and throw in a few stores where maybe someone will download this application for themselves.
I 'll have to take the time to write, and I'm wondering if it's worth ...
I'm interested in the following questions.
1. The app will be free, who should be aware of the ads? I mean, when programming, I will have to take into account (calculate) an additional space in the layout for advertising? How does she even look? Or is it all automatically built in, for example, with "Google Play"?
2. I downloaded some of the most popular free applications, I did not see ads there. What do they earn?
3. If advertising, how is the calculation going? Clicks, impressions? In what equivalent? For example 1000 impressions or 1000 clicks?
4. If the application is adapted into several languages ​​and in the case of one in a million, for example, 100,000 thousand users will download it. What is the approximate income? (stupid question, but offhand) ...
The application is not a game, it will just provide certain functionality. Well, if we take it into account that they will use it constantly and, for example, look at it at least once a day. An ideal option, very little has been done yet, but I want to dream.
Thank you.

Answer 1

1. You
2. Probably didn't look much. But there is a nuance when they promote the free version in order to buy a paid one.
3. Clicks. The average value is different for everyone, but approximately equal to 100,000 views = $10 in click-through revenue.
4. The question is not only stupid, but also not entirely clear.

Answer 2

Where do you read about app promotion in general?