@Riot please tell me how to I rebind move and attack to left mouse button.

the game isn't letting me. when I click on an action to rebind it. it doesn't let me rebind it to the left mouse click. How DO I DO THIS. my right button broke and I want to use the left one now please tell me I've been looking for a fix all day and I can't find it.

BASICALLY. what I want is that everything the right mouse button did be moved to be done by the left button. please