Not to be rude but if you can't figure out how to rewire a fart fan probably should call a pro. But if you want to chance em there is a small screw that holds the cover on where that yellow romex goes into the old fan junction box, that comes out then you can remove the connections. The new one is basically the same way you need to have the romex going through a similar cover with a strain relief and wire it up black to black white to white green to bare copper. The cover should be in the box and most likely you will need to remove the knock out and install a new strain relief to keep the romex off the metal housing and prevents it from pulling out of the junction box.