How to change shortcut for ´box select´?

how to change shortcut for ´box select´ in the prefrences?
and how can i change the shortcut for selecting items bc i dont want it to be left mouse?

Blender PreferencesKeymap :

  • Preferences: Select with Mouse Button : …

for shortcut:

  • Name : type “box select” under 3D View see: Keyboard: B … change…