So how is salama both "peaceful" and "hello"? Is it something like a homonym in english?
'Salama' on its own is not a greeting, unless it's shortened from 'Uko salama?/U salama?' to just 'Salama?' (the former implies the latter), which is 'are you well?'
'Peace' is a common greeting in Semitic languages
I thought salama meant safe and amani meant peaceful. What does amani mean/ when would I use it?
Peaceful it's translation is amani not salama