The main things necessary when setting up an attribute handler are an attribute database and a modifier database. Each of these databases can be used by all characters, because there could be a few attributes from the database per character, as seen below in initialization. The attribute database contains a list of attributes to be used in the game, such as strength, agility, health, armor, or whatever else is needed. Each attribute's value can be manually changed, or it can be changed with modifiers. These modifiers are initially stored in a database, but can be added or removed as needed from attributes.
Before you can use attributes, you have to add them to the attribute handler from the handler's attribute database. To do this call the AddAttribute function on the attribute handler.
Experience handlers are simple to set up, with setting up the initial variables detailed in the getting started guide.