Five Essential Things you need to know to Make Jewelry." Rather than do it all with diagrams and iambic pentameter, (what was I thinking?) - I've made a little video for you. Let me tell you - writing verse is easier. Much easier. I have a whole new appreciation for how slick the video and film that we take for granted is.
Anyway, in a nutshell - a crimp is a crushable bead that is designed to grab hold of wires and, after being crunched into place, hang onto the wires and hold them securely. Make sure that the crimp is sized proportionally to the wires going through it - not too sloppy - and crush the crimp so that the mark it makes down the side is between the two wires or cables or whatever you're stringing on. The next step, for a tidier look, is to fold the crimp up on itself. Note, this only works for crimp tubes - as there are round crimp beads - which you just crush flat. I find that it doesn't really pay to buy low end crimp beads - the aggravation of having them fail far exceeds the cost savings.
Then - to finish this off for a completely polished and professional look - add a crimp cover - also shown in the video. I hope. Gosh, I hope this works. And that you find it useful.