1. Select an audio clip and in the Inspector > Audio tab and set Pan Mode to Default. Now you can move the audio of that clip to your Left or Right audio channel by dragging the Pan Amount slider.
2. Detach Audio does what it says: it detaches the audio from a video clip. Your video clips don’t have any audio (at least not on the screenshot), so there is no audio you can detach.
Your audio clip in the screenshot is a connected clip. Connected clips are always attached to the Primary Storyline. In your case it is attached to your first video clip on the Storyline. But you can move it freely by just dragging it under another part of the Storyline if you wish.
If you want to move the video clip without moving the attached audio clip: hold down the Tilde key while moving the video clip.
These are indeed very basic things. You will learn FCPX much faster if you first read the manual before you start playing around with FCPX. There are also many free basic tutorials available on the internet to get you started.
– Ronny