You can store commonly used functions like indicators, so you do not need to retype them. Once an equation is stored, you can access it from any equation entry field by clicking on the small down arrow, which appears next to all the equation entry fields. It will then display a list of your stored equations.
You do not need to go to preferences to add, edit or delete stored equations. Each equation entry field will display a menu if you right click on it. It will give you the options to Add, Edit, Delete, or Manage. Most of these options are self-explanatory; Manage will display the equations preferences page.
You have to write the equations according to the English localization. For example you cannot write a number inside an equation as 17,17 (with comma as decimal separator). Instead you must write it as 17.17 (with point as decimal separator), regardless of the localization you're using. This rule applies only to equations; all other numbers in Venice follow the selected localization.
You can reach the equations page by: