use it exactly as "Good Morning" (before noon), use Buenas Tardes after noon,
to say "hello" you can also use Hola, Buen Dia (good day) or just "Buenas" (at all times)...
Buenas Tardes
"¿Buenos dias, Senorita (name), cómo esta?" (How are you?)
Buenos dias Alberto mean "Good Morning Alberto"
Buenos: Dias Noches Senor Senora
"Good morning to you" in Spanish is "buenos días a usted / ustedes / ti / vosotros, as"
Good morning = buenos dias
In buenos dias, there is only an accent over the 'i' in the word dia.
buenos dias, como amaneciste? buenos dias, has dormido bien?
Buenos dias is not a question soliciting a response, technically. However, the usual response is probably "igualmente" (same to you).
mundo de buenos dias means good morning world
buenos dias = good morning in spanish
'good morning sunshine' in Spanish is (word for word) 'sol de la mañana buena', but I think you mean 'Good morning, sunshine' (a greeting, plus 'sunshine') Good morning = Buenos dias 'Sunshine' as an affectionate nickname is not usual in Spanish, but literally = solana. So 'Buenos dias, solana'.