Like previously said, drip drops on the screen inside the head until wicking material is fully saturated, may take 5 - 10 drops.
You should see the material in the wicking holes in the side of the head become translucent, a few drips may come out of the wicking holes.
Thread head into base, fill tank, thread base & tank together, take a few un powered primer puffs (inhales without pressing the fire button), you should see a couple to a few bubbles rise from the wicking holes/base area.
Let it sit for a few minutes, 5 or so.
Set your power device to a low power level, like 7.5 - 8 watts, take a few vapes, you should see a bubble or two rise, this tells you it is wicking.
Gradually increase power over the first half tank to full tank to allow the head to break in & prevent burning.
If you get a dryish hit or even a hint of burnt taste turn the power down, hold your finger over the air inlet and give it a few light un powered primer puffs to draw liquid into the head.
Some e liquids / flavors / flavorings, dark or colored and especially sweet flavors tend to burn easy, clog wicking material & gunk coils rapidly.