The earliest position is the player to the immediate left of the big blind. This position is referred to as the under the gun  or UTG position. This player is required to act first postflop. You must not be seduced into playing pretty  hands such as small pocket pairs and small suited connectors at every opportunity.
CO  cut-off (the seat to the right of the button) MP  middle position : the seat to the right of the cut-off. EP  early position , also known as UTG ( under the gun ). The first player to act, pre-flop.