[Pharo-dev] Morph Events

I would like to understand how morph events work. I want to able to detect when a mouse was clicked inside my morph and also to handle keyboard events. Generally I want to be able to handle all events while the mouse cursor is above my morph. How I do that ? for example I have found Morph>>handlesMouseDown: evt but I am not sure what evt represents here. Whats the role of HandMorph in all this ?