You have to drink a chalky thick liquid, wait about 15 minutes then they take a xray to see where the barium is. Deoending om whehter it is upper gi or small bowel or both, the timing is different, they make keep taking xray every 15 minutes until it is in the spot they want to look at. Then they put you on a table and they use a wand with a camera in it to take the pics. It is on a TV screen so you can see sometimes. They make you move around a lot for different angles. Afterward you need to drink a lot of water and your stool will be white. The worst part is drinking the barium mixture.
Good luck!