Translation: Cuando yo caminaba, vi...
walking the runway in Spanish would be caminar por la pista
pasear al perro
Me viste en la escuela - You saw me in school.
Paseando en la alameda.
Te vi hoy.
you were walking in a circle and u saw a piece of paper so you picked it up and what did it say?
vi a su nena
Translation: Lo vi OR Lo he visto.
Translation: Acabo de ver
Yo ya lo vi.
estoy camminando a la casa y estoy cansado
In the case of I have seen it would be "yo vi" the verb ver is "to see" in spanish. vi is the singular past tense conjugation. For a saw that cuts use sierra to say I am cutting with a saw I'd say yo sierra utilizo...the singular form of utilizar but there is probably a better way to say this.