Take a look at this YouTube video that goes through all the steps of removing and replacing a key cap on your laptop. It should give you everything you need to know, but if you still have questions come on back and we'll do our best to answer them.
[link|https://www.youtube.com/watch?v=FplP-E_kUeE|How To Fix - HP Chromebook Key Replacement Repair 11 G3 Model Small Normal Sized Keys Letter Number - YouTube|new_window=true]