Answers in bold and underlined.
El otro día yo  fui  al supermercado. Yo  compre  vegetales, leche, arroz y fruta. Al salir me encontré con mi amiguita Jenny. Ella me  saluda  y me dice  “Hola, Victoria.” Después de hablar unos minutos, nosotras nos  despedimos . Al llegar a casa yo me di cuenta que la puerta  estaba abierta y yo  sabiendo que la había cerrado. Yo  entre  en la casa y  podia  ver que mi madre  estaba  cocinando algo para nosotras. Fue una sorpresa.
Translation:
The other day I went to the supermarket. I buy vegetables, milk, rice and fruit. On the way out I ran into my little friend Jenny. She waves at me and says "Hello, Victoria." After talking for a few minutes, we parted ways. When I got home I realized that the door was open and I knew that I had closed it. I entered the house and could see that my mother was cooking something for us. It was a surprise.