OK, lets try some simple bullet points:
A three phase motor has three stator windings.
There are two ways to connect those three windings, "star" and "delta".
In the Star (sometimes referred to as a Y (wye)) configuration, one end of each winding is connected to a common point (the Star Point).
In the Delta configuration, the windings are connected end to end in a closed loop.
For both star and delta connections, the phasing of the connections is important.
If the individual windings are rated for 240volts, then a delta connection will run from a 240v three phase supply.
Reconnecting into a delta configuration will enable the motor to run from a 415volt three phase supply. (240 x √3 = 415).
So, Delta is the "low voltage" connection and Star is the "high voltage" connection.
When a three phase motor is is connected to a three phase supply, it will start to turn.
If the motor turns in the wrong direction, swap over any two of the three connections and the motor will turn in the other direction.
When a three phase motor is connected to a single phase supply, it will just sit there humming to itself.
If the rotor is turned (by hand? Mind your fingers!) the rotor may spin up to normal speed, but the power available from the motor will be limited.
This fudge is sometimes used to make a single phase to three phase converter.
Does this help?
JimB