There are many different kinds of software for notating music.

One we will use is free online: MuseScore

First, you need to learn the names of the piano keys:

piano keys

Treble Clef Note Names

Bass Clef Note Names

Do the piano key/staff worksheet before beginning the project.

MuseScore Project 1: Naming Notes

MuseScore Project 2: Rhythmic Composition

MuseScore Project 3: Composing a Melody