@bruces So long as the pawns protect each other they can close up the board and force hand to hand combat where they have numerical superiority.
So pawns advance in rows, the leftmost front pawn moves, then the one behind it moves, repeat for another column, perhaps of the same colour. Then repeat until both rows have advanced. In that way the pawns advance with the front rank protected.
Elite strategy is pick off stragglers or make sacrifices to break up the pawn's ranks and get behind them.