This perfectly illustrates the problem with the Internet as a whole in the age of smartphones.
Your idea of the “first step” is always “open app” but the Internet is not apps. The Internet is servers, and a web browser is the client app for most of it.
Since I know how to use the Internet, it was simple AF to get a Lemmy account going. I went to lemmy.world and signed up. Now I’m on Lemmy.
If all you know of the Internet is “open app” on your phone, you have a lot more to learn about the Internet as a whole.