Place object on Hololens based on three user defined points

Hey there, what I want to do is placing an object. The objects orientation should be given by previously set vertices of the object ( by other objects or anchors, the position of those should be predefined in unity). example: I want to place a box. when i first tap the position for the upper right corner is set. the next tap is for the lower left corner and the same thing with a third point. So I can orient my object precise in the room (see attachment).