"Primer piso" means "first floor."
first or primary fact, or first done or made.
It means "The first month of autumn is.."
Primer beso translates into English as My First Love as well as My First Kiss. Occasionally it translates into My Girl (the movie My Girl is indeed called Primer Beso in Spanish speaking countries).
Primer = "first"
The Spanish phrase "mi primer dia sin ti" means my first day without you. This is a literal translation and could be interpreted in several different ways.
Mi Primer Millon is not a correct Spanish phraseLiterally translated: My first million
En el primer piso
amor a primer vista