there is only one way that the CPU will slip into the slots. There is a corner cut out usually that will block the CPU from being installed any other way than proper way. it looks right, and bottomed out to the holder.
CPU fan... well you need to clip the CPU in first with the original retainer from motherboard.
is your CPU fan aftermarket? or stock one?
stock one can be installed in many different ways usually, is not a problem if the wire to power the fan reaches
aftermarket fans you want the fan to sit vertically, so that it can pull air from front of PC case and out towards back of the PC case where the hot air gets taken out of the case
but, it would be very good for you to watch some youtube videos as you can see on hand how to do it properly