As a composer who want to engage with spectral knowledge I decided to start learning Open Music by myself.
Fortunately I live on the XXI century and I can learn what ever I want on Youtube. So that's what I am doing: I am watching a few tutorials about open music and learning how to work with the IRCAM's software.
First, I learned how to create a note and a chord. How to link different chords and have them on the same stave.
Second, I learned how to create a harmonic series converting a list of midi cent pitch(es) <midics> to frequencies (Hz) (image 2)
Then, I learned that I can click twice on the box at the bottom-left and have a window, where I can change the harmonic series as a chord (image 3) or putted in order (image 4). In both cases I can hear the sonic result.
Nonetheless, it is a bit annoying to write all that symbols to have a harmonic series. So, I learned that I can have a symbol, called 'arithmetic series' which give me all pitches I want of a harmonic series, odd partials, pair partials, etc (image 5, 6 and 7).