Follicle scan question!

Last cycle, I had to go in for two follicle scans. The first one, the nurse just took my blood pressure and left. Then the Dr came in, gave me the sheet and told me to empty my bladder and get ready while she set up. At the second one the nurse told me to empty my bladder. The Dr came in and was like "oh, you're not ready yet?". Like I was supposed to already be sitting there pantless. But the nurse didn't tell me to get ready or give me a sheet.

I'm going in for a follicle scan next week and I have slight anxiety about what I'm supposed to do 🙈 Do I just go to the cabinet and grab my own sheet and already be ready when the Dr comes in? Or do I wait for her?

As you can probably tell, I'm a newbie at this lol