。
I came here on foot.
Literal
Walk-and came (polite).
やってくる is a compound verb from やる ('do') + くる ('come'), meaning 'come over, show up, arrive' — with a slight emphatic or colloquial flavor compared to plain 来る. やってきました emphasizes the arrival as a completed journey. Paired with 歩いて, the whole thing is 'walked and arrived here.'