One 3.5, One 2.5*, and one 5.25. You don't need to mount the SSD in a bay, you can attach it to the back of the motherboard area on some cases.

? Power supply does not take a bay.

Note that a number of modern computer cases has bays that can hold 2.5" or 3.5" drive.

most drives are mounted in an internal 3.5 bay. In your case, the HDD and SSD should be able to go into 1 each, but if you're pressed for space, you can attach it to another area like @kiyoshi_ said. The ODD goes in a 5.25 external bay and psus don't take up a drive bay

Thanks everyone, my case had way more bays than I needed (I actually ended up taking out the middle cage for better airflow and looks) and my SSD had screw holes to fit into one of the 3.5 bays.