So essentially the match has positions, this is essentially describing what both wrestlers are doing. Both standing for example means that they are both standing, Standing while opponent on back means one girl is standing, the other is laying on her back. Some are situational - like After Match Humiliation is for a post match type penalty, (After Match Humiliation for KO is for when the opponent has been knocked out).
Within these positions are moves... so for example a camal clutch is possible if the one wrestler is standing and the other is laying on her stomach. The simulator basically takes the wrestler who is in the attacker position (in this case standing) and then uses her moveset to determine which move she would use. So a scissoring moveset might mean it's more likely to use a headscissors, where as the facesitting moveset means she is more likely to go for a face sit.
When both wrestlers are "even" (ie both standing, or both on knees), the simulator will use their strength, quickness, technical skill, and current condition to determine who gets the advantage. With the advantage, a move is selected just like above.
As the holds are applied, moves incur damage to different body parts. A headscissors will hurt the head and stamina of an opponent, a boston crab the legs and back. Once any of these areas are hurt long enough and a move is applied that hurts them past a breaking point, a submission occurs... in the case of stamina it might be a knock out.