We tag turnovers in the context of the offensive team. That is, the mental model you should be using for a turnover is "we turned the ball over to the other team" - ie, "we lost possession of the ball". A ball can be turned over in several ways, but the two primary concerns are the actions which caused the turnover to begin with.
Forced Turnovers occur (and should be tagged) when a defensive player directly causes the offense to lose the ball, and subsequently gain possession of the ball. This could happen due to a defensive stick or body check, knocking the ball out of the offensive player's crosse. Note that if a forced turnover situation causes a ground ball, these need to be tagged separately. Here's an example: team 1 has possession, and team 2 checks the ball out of team 1's posesssion, which causes the ball to fall to the ground. Team 2 recovers the ground ball, gaining possession. Since the forced turnover happened first, we tag "turnover" on team 1, marking it as forced. We then tag a "ground ball recovered" for team 2, who at this point is now the offensive team in possession of the ball.
Unforced Turnovers occur when an offensive player loses possession of the ball in a way that is not influenced by a defensive player or a penalty, and the defensive team gains possession. Examples of this could be dropped passes, trips, or dropped balls from the crosse. Unlike Forced Turnovers, we can safely stat an unforced turnover in a ground ball recovery by the defensive team. If team 1 has possession, but loses the ball in an unforced manner, tagging a ground ball recovery for team 2 will insert an unforced turnover on team 1.
Unforced turnovers are only counted on ground ball recoveries that change possession of the ball, and further, only on non-shot situations. If the ball is shot (either on-goal or off-target), a ground ball recovery (regardless of which team recovers the ball) cannot result in any kind of turnover, as per the NCAA rule book. If a shot is tagged, and then a ground ball recovery, an unforced turnover will not be inserted.