First appointment tomorrow!

Hubby and I are so so excited!! Our first appointment is tomorrow night and along with that is our first ultrasound! I'm just a little confused tho, I called them to ask if the scan will be transvaginal or abdominal.. She said it would be abdominal and when I asked if I needed to drink the 32oz she said no it's not necessary.. Just a little confused as to why I don't need to drink and how are we gonna get a clear picture? I'll be 8wk5d. Thanks ladies!