Question about my torando 14.4 v electric drill, probably has nothing to do with the model though?

Question:I've got a tornado 14.4 v electric drill but im inexperienced and I dont know how to get the tip thing off so I can adjust the screw size I need to use. Any help or links is appreciated, Thanks.

Answers:
If you are talking about changing the bit, you hold the large plastic part of the chuck and put the drill in reverse. This will release the bit. Change bits, hold the chuck and put the drill in forward to tighten the new bit. If there are round holes in the chuck and gear looking teeth, you need a chuck key.