YOU SAID:

I saw a large man wearing a jacket being walked by his dog

INTO JAPANESE

私は彼の犬が歩いているジャケットを着た大きな男を見た

BACK INTO ENGLISH

I saw a big guy in a jacket where his dog is walking

INTO JAPANESE

私は彼の犬が歩いているジャケットの大きな男を見た

BACK INTO ENGLISH

I saw a big guy in his jacket where his dog is walking

INTO JAPANESE

私は彼の犬が歩いている彼のジャケットに大きな男を見た

BACK INTO ENGLISH

I saw a big guy in his jacket where his dog is walking