I have two questions.

  1. How do I get MuseScore icon attached to Icon Task List? Usual way of clicking the star does not exist with AppImage.
  2. Can this be done with just a few mouse clicks? If not, what would be the most easiest and fastest way to just get it done?!

  • If it dosen't work out the box, why not use the flatpak version?
    https://flathub.org/en/apps/org.musescore.MuseScore

    If you haven't used flatpak befor:
    Open your terminal:
    $ sudo eopkg install flatpak
    installs flatpak, you can also use the software center for this.
    $ flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
    adds the flatpak repo to Solus
    Reboot
    Open console
    flatpak install flathub org.musescore.MuseScore
    Installs MuseScore

If it dosen't work out the box, why not use the flatpak version?
https://flathub.org/en/apps/org.musescore.MuseScore

If you haven't used flatpak befor:
Open your terminal:
$ sudo eopkg install flatpak
installs flatpak, you can also use the software center for this.
$ flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
adds the flatpak repo to Solus
Reboot
Open console
flatpak install flathub org.musescore.MuseScore
Installs MuseScore

You'd need to create a .desktop launcher for it. It's probably easier to just use the Flatpak which comes with a .desktop launcher already.

@Phiqu. Although this was an answer that I didn't expect or look for, it worked great! And it was very easy copy/paste from your answer, thank you very much! Problem solved.

I needed only install-part of it because I remembered that I'd just recently and first time needed software *(alsa-scarlett-gui), which was available only flatpak, so I had already done installing flatpak + added flathub repository.
*https://github.com/geoffreybennett/alsa-scarlett-gui

@ReillyBrogan Thanks for confirming Phiqu's advise, it was indeed quite simple task although leaves me, again, wondering why is this seemingly simple task, relatively complicated. But, perhaps new thread for that.