MECHANICS OF SET PLAYS

Restart
Referee Position
Lead Assistant Referee
Trail Assistant Referee
Kick Off
Just outside center circle in the half of the team kicking off.
In line with second to last defender.
In line with second to last defender.
Goal Kick
Midfield, or near where you think ball will land.
In line with second to last defender or at halfway-line.
At goal-kick end, first at six yard line and when ball has been correctly placed move to 18 yard line.
Corner Kick
In corner of penalty area of behind goal-line between 6 and 18 yard line.
Outside corner flag or on goal-line as instructed by referee.
In line with second to last defender or at halfway-line.
Penalty Kick
On field in line with six yard line between goal-area and edge of penalty-area. Positioned to (1) ensure kick is taken properly and (2) watch for encroachment and  (3) ensure goalkeeper does not advance illegally.. assistant referee should be acting as goal judge.
At intersection of goal-line and penalty-area facing the goal.
At halfway-line ready to move quickly into position in line with second to last defender.
Free Kick Near Goal
On or near diagonal, near wall to watch for infractions and, if necessary, to judge off-side.
At goal-line or in line with second to last defender depending on referee's instructions.
In line with second to last defender or at halfway-line.
Free Kick Not Near Goal
To handle possible encroachments and to reach center of play quickly...roughly on diagonal.
In line with second to last defender.
In line with second to last defender.
Throw-in
On referee side of field, move slightly off diagonal toward touch-line.  On assistant referee side, move from diagonal toward center of field.
In line with second to last defender.
In line with second to last defender.

NOTE: All of the above will vary depending upon circumstances - age and skill of players, etc.

NOTE: If the second to last defender moves into the opponent's half, assistant referees would stop at the halfway-line until that player returns to his or her own half.

FROM: Interpretations, Instructions and Advice for Referees, July 2001.