"Where are my green shoes?"
Translation:¿Dónde están mis zapatos verdes?
Dónde is interrogative pronoun 'Where'
Adónde is actually a contraction of a + dónde meaning something like 'To where' (when verbs of movement are present such as 'go'). We tend to use constructions such as "To where are we heading?" which sounds weird in English, but fully natural in Spanish.
Rule of thumb: if there is not a verb of movement, use dónde (or donde)
Where did I leave my keys? - ¿Dónde me he dejado las llaves?
This is the place where the event took place - Este es el lugar donde el suceso tuvo lugar.
We are going to a place. + Where are we going (to) ? - Estamos yendo a un sitio. + Adónde (a dónde) vamos?
It is always good to have a home to take a loaf of bread to - Siempre es bueno tener un hogar adonde llevar una barra de pan [example extracted from Maruxa Vilalta: Una mujer, dos hombres y un balazo]
Same as other verb conjugations
e.g., "comer" (to eat), "come" (you eat), "comen" (they eat)
so, "estar" (to be [temporarily]), "está" (you are [temporarily]), "están" (they are [temporarily])
and, "ser" (to be [permanently]), "eres" (you are [permanently]), "son" (they are [permanently])