Reaper 1313,

2nd or 3rd up refers to the numbers in any form guide before the horse's name. S124 means a spell [S] and the the horse's placing for the next 3 starts. This run would be the 4th start [4th up]. 15 without and X in front of the 15 would mean the horse has only ever had 2 starts. So it would be 3rd. up this start. Get the drift?

Bet either win or place only. You will get returns more often for the place but you will get lousy odds compared to the runners win odds and you would have missed some great win bet odds.
I only ever [well mostly] bet for the win. I don't bother with this system on weekend as there are too many race meetings, which doesn't mean the system can't win on weekends. I would ignore the main city metro race meetings though.