Music stream from my app?

I'm very new here and I have a question.
Being the amateur musician that I am, I'm recording some of my music that I want to play in an app I'm going to make with appinventor?
To play 2-3-4-5 music tracks one after the other with pause, stop, next, previous buttons.
Is there an option here to do that? By the way, is there a tutorial on how to do something like this?

And one more question: What size should be the mp3 files in order to be able to upload them to the corresponding application that I will make?

Here is how to handle a play list (but with a different component.)