Take the cart off the atomizer and you will see some filler, if not it's the blank that comes with atomizer, just throw it away, the empty cart. Drip your juice onto the filler, I usually pull it out a bit and put some juice down into the bottom of the cart, then carefully push filler back down and drip juice on filler until it is wet. I fluff it up a bit so it's level with top edge of cart and then just pop it on the atomizer and voila you're ready to go. I would put a drop or two on the atomizer it seems to wick better that way.