You have a blue wire and a brown wire.
Blue has an 'L' in it and Brown has an 'R'
So, the blue wire goes to the left and the brown to the right
(and if they've given you an earth that only leaves one place for it to go)

Trouble is, rkay, that I invariably hold the plug with the wire pointing away from me! Is this why the fuses in my house are always blowing?