playing a pgn in Arena

[evergreen1]

i found that pgn file can be loaded into arena and it will play automatically the moves.
there is a button under the movelist >demo.
click on it and it will start the moves,
But after the first move it displays a message which says>
ADD NEW MOVES
NEW VARIATION
OVERWRITE
and i am not able to play the moves as it is. the original moves are not playing irrespective of whatever selection i made.new variation or overwrite. any clue please? i want to play the moves as it is in the PGN and if it is in winboard.thanks

[evergreen1]

ok it has been told by a friend that to get the pgn play automatic you have to opt for replay. now please advice how to adjust the speed of replay? is it possible to stop the replay at a certain point,or move? thanks