To modify basic types, use the GDE Data Classes you generated. I’ll use this Warrior item to demonstrate how to modify its data.

GDECharacterData warrior = new GDECharacterData(GDEItemKeys.Character_Warrior);

warrior.hp += 100;
warrior.name = "Celestipoo";  

Please note GDE no longer uses PlayerPrefs to persist modified data. To persist your data, call the new Save method when it is convenient in your game. Be sure to save as often as you need. Web builds still use PlayerPrefs (Save and ClearSaved methods have no effect in Web builds).

// To persist modified data call.. 
GDEDataManager.Save();
  
// To clear any persisted data call..
GDEDataManager.ClearSaved();

These are the basic types supported:

bool
int
float
string
Vector2
Vector3
Vector4
Color

// These types are supported, but are Read Only
GameObject
Texture2D
Material
AudioClip