i am wanting to find live wires and earth wires around my car, and my http://images.kenwood.eu/files/prod/754/5/DDX7200_Inst.Man_(EN).pdf kenwood 7200

Maplin > General Purpose Analogue Multimeter (http://www.maplin.co.uk/module.aspx?ITAG=FAQ&ModuleNo=25414&doy=6m10#faq)

i've no idea how to use these, but it seems kinda handy as i seen builders and sparkys use em

Set it to 12V or more DC, stick the black on your chassis somewhere & poke the red into terminals. When the needle shifts you have a live, also flick the ignition on & off to find the switched lives.

i bought this today http://www.sinometer.com/Products/Electronic%20meters/Digital%20multimeters/MS8230B.jpg
correct me if i am wrong,
black needle plugs in the middle,.
red one goes on the "mA"

set it on......the 20 on the, left below V
or the other two? 20m , 20k
if i wanna test the rear lights, theres no chassis, where do i poke the back on?
and obviously poke around with the red?

if no change its earth?
if the digits change it is a live wire?

Check the manual but yup sounds right for connection & yup set to 20V DC. Not sure what you mean by no chassis, any metal part of the car can be taken as earth/black. As you say if your reading goes up youve got a live, normally no less than 10v with engine off & up to 14v running.
To help yourself a little try downloading a wiring diagram, if you do a search you should find a couple of links on here.