Early pregnancy scan

Have an early pregnancy scan (first one) this week due to some issues so have to check that there is a sticky bean and is a heart beat. If all is ok the dr has estimated i will be approx 8-9 weeks.

Looking for some advice on how much to drink how long before a scan to get best chance at a clear view! Id Squash ok or does it need to be clear liquid. Help please. Praying for a sticky bean!🤞🏻

Update- my dr has told me to go tothe ultrasound department with a full bladder..