Are shin guards required and how do substitutions work?

Shin guards must be worn by all players without exception, and the Game Leader should check every player is wearing them.

Substitutions: players may be rotated on and off at any time. A coach or parent may substitute while the ball is in play, provided the player is off the field before the substitute goes on. Equal playing time is a priority so all players, regardless of age, gender or ability, get on the field. Substitutes with space on the sideline should be encouraged to set up small-sided games or practise skills in a designated area without interfering with play.

Source: Coles MiniRoos National Playing Formats and Rules, https://www.miniroos.com.au/club-resources