what to expect at 6-7 week scan

i am going for a scan tomorrow,, first one! can anyone enlighten me if it will be transvaginal or abdominal, will i see or hear a hb? what will baby look like? a dot? a baby? alien? any pics u have would be great. im 6 weeks 6 days according to opk and about 7 weeks 4 days according to lmp