For Fleming's left-hand rule, write down the three things that are 90° to each other, and next to each one write down the finger or thumb that represents it.
The three things that are 90° to each other, and next to each, and next to each one are:-
Current- it is denoted by the direction of the centre finger.
Magnetic field- ii is denoted by the direction of the fore finger.
Force or motion- it is denoted by the thumb.