How do people usually promote their project?

Question

How do I make my friends, my friends' friends, my friends' friends' friends, and other strangers use my app?

I know this is such a broad question, and solutions may differ from app by app, but I just want to ask this to get the big picture.

I made an app called Atrable, where you can share your daily moments with others, using either audio or video. The difference from other social media is that you have to record audio to post, so that others can vividly know what you're doing. This way, I thought people would start sharing their undecorated moments vividly.

Problem here is that only 14 people (including me, my friends, my parents, and Apple Appstore Connect reviewers) use this app. I thought my friends would share Atrable to their friends, but they didn't. I can't blame them, but I have no idea how to "naturally" encourage them to share the app with others.

I also made a video, but it's only gotten 20 views so far.

I don't want to pay money to advertise it though. It's like my side project, and I'm not even sure if the app deserves it. When I advertise it, I also feel like I'm gnawing the app's value by myself.

So, back to the question, if you have experience on making your own project and getting some decent amount of return from it, could you share your experience?