Using the Behringer HA8000 V2 is quite straightforward. First, connect your sound sources to the direct inputs on each channel or use the stereo main inputs. You can then adjust the output level for each channel using the level control. The LED output meter will show you the output level accurately. For more flexibility, you can switch between mono and stereo on each channel. When connecting headphones, you can use either the front or rear TRS phones connectors. If you need to connect multiple headphone amplifiers, use the parallel main outputs. As for maintenance, keep the amplifier in a clean and dry place. Avoid exposing it to extreme temperatures or humidity. Also, make sure to turn it off when not in use to save energy. The switching power supply is designed to work with a wide range of voltages (100 - 240 V~), so you don't have to worry about voltage compatibility when traveling.