Why can't I share my creations?

I've made some songs but it seems like I'm making it wrong, because if I copy the folder or package from my computer and then I paste it in another computer, the beatmap is not there.
Maybe I need a codec or something like that. Help!

Are you going into the in-game editor? If you are, are you sure you're pressing save?
Are you sure you're copying the right folder? Did you go into options and select "Reload Song/Courses" after putting the folder on the other computer?

(Ah... I'm not that stupid ¬¬) I've pressed every single button in the exporter and the editor. I can play my own songs in my computer, but I want to make a file that I can share. Making a package and then put the arrows didn't work, neither a folder with the mp3, the banner, the background and a SMfile.
PD: if I make mistakes on writing it's because I'm not native english speaker.