There are a few things you want need to think about when choosing the correct sup surf break for you.
1. Surf Shape
Sean suggests slow and soft waves for you to practice and gain your muscle memory so you can go tackle more aggressive waves when you are ready.
2. Wave Height
Wave height is critical in making sure you are having fun and learning properly as a beginner. You want to stay in the ankle to waist high range (1-3ft) at the beginning to keep yourself and others in the water safe. If you try and surf larger waves right off the bat you will most definitely be getting trashed and putting others in danger.
3. Crowd Factor
As a beginner, you will want to find a break with the least amount of crowd to avoid any obstacles as you will need to learn proper maneuvering on your sup in waves. If other people are in front of you while riding in you may cause serious injuries to you both. To be safe surf away from others while you are learning so you can have fun and learn to fall and sup properly.