One thing I didn't grasp at first was:
Take the voltage of the cob (36v) and multiply it by the amps on the driver (
HLG-185h-
1050a in this case the amps are 1.05, there's also 1400a, 2100a etc)
36x1.05=37.8
Now you take that number and however many times you can divide it into the wattage of the driver (185 in this case, there's also 120,240,320 etc) is how many cobs you can fit.
185/37.8=4.89. Now you can technically fit 5 because it's close. I am not positive why that is, I still have much to learn.
If you had a Meanwell
HLG-240h-2100a with 36v Cobs you would take 36x2.1 and get 75.6 and you can run up to 3 for a total of ~225w (3 36v Cobs at 2.1amps for ~75w a piece).
This is just the very basics, I hope it helps get you started and if I have a concept wrong please someone let me know.