Click fire button, nothing happens: This is an easy one to overlook and fix. The package comes with 2 coils but none installed, and the chimney is easily mistakable for the coil. Just screw on the coil to the chimney (don't forget to prime a new coil: a drop or 2 down the center, and then let sit in full tank for a few minutes).
Another issue can be the coil not screwed on correctly, causing a lack of or bad contact. Just unscrew and screw back on correctly.
Finally, if these two fixes don't work, it could be a bad coil. Replace the coil.
Gurgling and/or spitback: The coil has flooded. This can happen with these type coils when the chamber is overfilled, even slightly. The liquid will have nowhere to go and so will oversaturate the wick. Remove the cap and chimney and unscrew the coil. Remove any excess liquid, either by blowing or with something absorbant. Be careful not to disturb the coil!