John 1:32

καὶ ἐμαρτύρησεν Ἰωάννης λέγων ὅτι τεθέαμαι τὸ πνεῦμα καταβαῖνον ὡς περιστερὰν ἐξ οὐρανοῦ, καὶ ἔμεινεν ἐπ' αὐτόν.

καὶ conjunction "and"

ἐμαρτύρησεν verb aorist active indicative 3rd singular from μαρτυρέω (I testify) "he testified"

Ἰωάννης proper noun genitive masculine singular "John"

λέγων present active participle nominative masculine singular from λέγω (I say) "saying"

ὅτι conjunction "that" (Note: here it is simply indicating the coming quote)

τεθέαμαι verb perfect middle deponent 1st singular from θεάομαι (I see) "I have seen"

τὸ definite article nominative neuter singular "the"

πνεῦμα noun nominative neuter singular "Spirit"

καταβαῖνον present active participle accusative neuter singular from καταβαίνω (I come down) "coming down"

ὡς adverb "as"

περιστερὰν noun accusative feminine singular "a dove"

ἐξ preposition genitive "out of"

οὐρανοῦ noun genitive masculine singular "heaven"

καὶ conjunction "and"

ἔμεινεν verb aorist active indicative 3rd singular from μένω (I remain) "it remained"

ἐπ' preposition with accusative "on"

αὐτόν pronoun accusative masculine singular "him"

Rough Word-by-word:
and he testified John saying that I have seen the Spirit coming down as a dove out of heaven and it remained on him

Smooth Translation:
And John testified saying, "I have seen the Spirit coming down as a dove out of heaven and it remained on him."