I second the warnings which RigDoctor has given.
Now lets try and give a little bit of insight into a 3 phase supply.
There are three phases, they are named Red, Yellow and Blue. If you are lucky the cable cores will be identified with those colours.
There is usually a neutral connection, but depending on the application it may not be used.
Measuring between any two of the phase wires you should measure 415volts, so:
R to Y = 415v
Y to B = 415v
B to R = 415v
Measuring between the phase wires and neutral you should see 240 volts. So:
R to N = 240v
Y to N = 240v
B to N = 240v
The power supply to a street of houses is three phase, the first house is connected to red and neutral, the second to yellow and neutral, the third to blue and neutral and so on down the street to balance the load on the three phases.
A three phase motor has three windings, and there are two ways of connecting those windings. The two ways are referred to as Star and Delta.
The star connection has the three windings with one end connected to a common point (the Star Point) which can be connected to the neutral line of the supply. The neutral connection is not necessary as no current flows in the neutral on a balance 3 phase system.
The delta connection has the three windings connected end to end in the form of a Greek letter delta. With the delta connection there is nowhere to connect the neutral, it is not required.
I think that is enough for now, it only just gives the minimum of information.
Be carefull there is no reset button on reality. Death is permanent.
JimB