This is the 585th most frequent Italian word.
andato
"Andato" means "gone" in English.
Here, "andato" is used as part of the past tense construction with "essere" in an idiomatic expression meaning that everything turned out well.
Tutto è andato per il meglio.
Everything went for the best.
In this usage, "andato" conveys the result or outcome, again as a past participle with "essere" for an event in the past leading to an undesirable result.
Il progetto è andato male.
The project went poorly.
In this sentence, "andato" is the past participle of the verb "andare" (to go), used in the passato prossimo tense combined with the auxiliary verb "essere" to indicate a completed action in the past.