Inserts are a break in the channel strip path so you can put other important stuff in. Most commonly used for dynamics processing, e.g. compression and gating. More commonly you will put FX like reverbs on a post-fade send instead. The signal leaves the channel at the insert point and comes back in at the same place, just having done a quick lap of your FX rack on the way.
The idea with 'tapping' inserts is taking the signal out and sending it to your recorder, and just not sending it back to the desk again. So you can't EQ or use your main fader for recording.
Now, onto desks. I would not really recommend the Behringer range ... the Yamaha MG range is very similarly priced and far superior IMO. Do a search on them on this BBS and you'll learn a lot. Mackie is overpriced for my uses but another good range to look at is Soundcraft. The E series look like a bit of fun, but the M series are where you start to get serious. A Soundcraft M8 would give you eight decent preamps with proper direct outs and all the bells and whistles a superior mixer brings. No crappy FX built in though.
