The connector for the ribbon cable has a lock. The grayish/brown top to the connector can be flipped up from the ribbon side and the ribbon cable then falls out. It is not designed to have the ribbon cable just pulled out. You should definitely flip it up to put the cable back.

Great guide. I would just like to mention a difference I found. My laptop had white connectors and the hinged lock latch was black. So I guess all assemblies aren’t identical. Also, the large connector for the keyboard did not have a locking latch. My model is an E5-571P manufactured 2014/09/15.