How and when does my ranking change after a match in a ladder system?

In order for the ladder ranking to be updated you must a) score your match and b) mark it as completed - just like you would for any other type of match. As soon as you complete the match rankings are updated.

If you set the score wrongly and caused the ranking to be updated incorrectly you must change the match back into pending state, rescore the match and then complete it again.

If you were the challenger (i.e. positioned below your position) and you lose then no change in the ranking takes place; You and your opponent stay where you were. If, as the challenger, you win then you get promoted to the position of your opponent and they get demoted one position.

There are some special rules that apply when people are first entering the ladder (assuming the organiser has not placed them at a relevant spot). This goes as follows:

• If you're new to the ladder you must win a game to get ranked into the ladder. When you do win, you'll be placed in the winners position.
• But it could be that your opponent is also new to the ladder and they too are as yet unranked. In which case, your opponent will stay unranked (being the loser) and you will be inserted into the ladder at a point that is commensurate with your rating as determined by ManageMyMatch. Thus, if you are rated high then you may find yourself placed further up the ladder so that you can immediately engage in more competitive matches.