get_global_mouse_position() and get_local_mouse_position() are both methods of CanvasItem, so if you’re using a 2D node, you can use “CallSelf” and call one of those functions.
Otherwise, your best bet is to add mouse click action(s) to the Input Map, and use the Input.is_action_pressed() function. You can get this from EngineSingleton → CallInstance.
They’re not really separated out. Honestly, VS is still very new so there hasn’t been much time for the community to contribute much in the way of documentation. I started to do some work with it, but honestly, I find it far more frustrating and cumbersome to use than GDScript, so I’m not really recommending it to my students.