How to create the second object from the first

Hi,

Check the attached images. I need to create the second image from te frist one. I tried creating nodes at the side lines of the first object so I can drag them and modify the object. But when I create those nodes I cant create them at specific coordinates. And also, when I drag the corners nodes up and down I can choose the amount that I will drag/move the node.

I really need exact nodes positioning to make this object cause I need it to have very precise measurements.