“فَ” (fa)a joining word meaning “then / so.” It connects this word to what came before.Corpus grammarCONJ — prefixed conjunction fa (then / so).
“أَنبَتْ” (ʾaan[bat)means “Then We caused to grow” in this verse. It is a verb. an action or state word. Here it is perfect verb, verb pattern four.Corpus grammarV — first person plural perfect verb.
“نَا” (nā)an attached pronoun meaning “we” or “us.”Corpus grammarPRON — first person plural subject pronoun.