How to be friends with a 10 year old?

My friend mom is going to start dropping me off at home from school since I dont like the bus. Well I only met her once and she adores me and I met her sister today when I went to say hey to her mom after school. Her little sister was there so I'm assuming she will be in the car everytime I ride with them. I said hey to her and she waved so I want her to feel comfortable around me since I will see her whenever her mom takes me home, I don't have a little sister or 10 year olds so I don't know what to say or act but I bought there mom some chocolate for taking me home and the younger sister a big bad of suckers so hopefully that will start us off. Any advice?