It occurs to me... Why don't they ever include a musical instrument in sentences with "suonare"? That would make the difference between "giocare" and "suonare" a lot clearer.
Good point! We'll see what can be done!
so why is it not correct to say "we ring on sunday"?
An object would be necessary for ring to apply here. You could ring the bell on Sunday, but there is no bell in this sentence, so the best translation is play (a musical instrument)
I thought that a phone was implied; as in, "we will ring you up (call you) on Sunday"
Why is it not "giochiamo" for play, as we were just shown and taught?
"Giocare" is for playing a game ("gioco" = game), "suonare" for playing an instrument ("suono" = sound).