Details on a Transvaginal Ultrasound

So I have my first OBGYN appointment in 2 weeks. They have me scheduled for an Transvaginal Ultrasound. I never heard of this, so I went online and started reading. All I've read about this are reasons on why they would do it.

I haven't read anything good. Just things such as eptomic pregnancy and internal bleeding, etc. I then have a "confirmation of pregnancy" an hour after. Wouldn't they want to do that before doing an Ultrasound?

Can people who have had this done give me some insight?