Microwaves are tricky, and that's why we provide the Test Launch packet with each Discovery Kit.
Naturally, every kernel isn't going to pop. It's normal to have roughly a dozen unpopped kernels, and we take that into account when we fill our bags to make sure you still get a full Popper Bowl of popcorn with each pouch.
The kernels tend to pop better when they are at room temperature. The kernels don't need to be refrigerated, but if you choose to store them in the fridge, make sure to bring them to room temperature before popping.
Are you using a "smart" microwave with sensor cooking? The popcorn setting is calibrated to the usual paper bags, so this setting won't normally work well with our silicone Popper Bowls. If you can, use the manual setting at full power to start. If it still doesn't pop well, try setting the power level to 80%. If you can't turn off the sensor, then a trick is to place the Popper on an inverted plate so it's slightly elevated.
Make sure that your turntable is in place so that the Popper is rotating properly and does not get caught on the sides- but it is better to place the Popper off-center rather than right in the middle. Importantly, check that there are no liquid spills- this can misdirect the actual microwaves and not concentrate them into the Popper where they should be.
It will be a bit of trial error, and you'll need to experiment with your microwave a little. If you continue to have trouble, contact customer support.