Enable AGC (File/Options/Audio/Input level amplifier) and set the level to 50-60 dB.
Use a filter (High Pass – 200 Hz) in the advanced filter settings dialog to dampen low frequency noise and hum.
The trigger sensitivity (front GUI) is typical a value between 0-200 ms.
Record a noise profile (the blue button at the front GUI).
Check the “Only on trigger” if you want to record the sound without filtering and only use the filter when triggering, by using this option it is possible to filter harder during trigger without affecting recording quality.