From the post:
In Aristeia! the most important effects are the Switches that can be used by any of the players, they are different depending on the Aristo. These abilities provide versatility and dynamism to the games and, on occasions, will flip your rival upside down.
Switches allow activation of certain effects from rolls that each character makes. To activate a Switch, the character must spend some of the symbols from the roll. These symbols will not be usable for anything else.
It is very important to keep in mind that the players must play the Switches after Rolling the dice from a Roll, and before resolving said Roll.