Musescore id really simple to understand, and there are many YouTube tutorials that help you if you don’t. It also gives you over 50 intruments to chose from, from teh classical piano, to the synths! Musescore is more of a note composition style, unlike FL studio and others, where they use more of a synthesia style. But, if you want, there is a feature, where you can make music with synthesia on musescore, although I’ve never used it. Musescore is free, but it comes with a cost: the sound quality is not that great (except for the piano).
This is where Audacity comes in. Simply export the song you created with Musescore as an mp3 and import it to audacity, where you can add effects like REVERB(my favourite!). You can also adjust speed and even add more “custom” instruments. I like to burp into the microphone and re-pitch the burp to make it fit into the music.