You want the three piece airlock to be filled up around halfway.
And leave your yeast alone to do their job. Some brews I make only have a few bubbles on the outer edge during maximum fermentation. A couple needs a blow off tube in a few hours. Just make sure you get one on before you need it.
Relax, enjoy it, the yeast know what they are doing. Your job is to keep the temperature at a happy level for them, and keep the brew out of direct sunlight, and give them a couple of weeks to do their job.
In Primary: Belgium Chimay clones.
In Secondary: Braggot, pale ale, end of the world white.
Conditioning: Mead, Cider, braggot, Belgium Wheat.
On Tap: Clones, Chimay Blue, Red, Porter, malted cider.
Bottles: Far, far, too many to list.