Simplest thing in the world. Here's a photo of one (it happens to be a Velocity):
That's the build deck. You put a coil on each side of the two little towers you see (the posts), and pull a bit of cotton through the center of the coil for a wick. Then you drip some juice down in the bottom of the thing (the well), wait until the wick saturates, put on the top cap, attach it to the mod and vape away. When the juice is gone, you lift the top cap, drip on more juice, and repeat. Here's two more photos of one that's built, the first is coils only, the second with a horseshoe wick:
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That particular dripper in the last two photos is mine, and I put that build in it last night. As luck would have it, mine has been modified for bottom feed to use on a squonk mod (you don't take the top off to add juice, you squeeze a little plastic bottle and it shoots juice up into it), but it's the same idea.