Here's how to insert cites using keyboard shortcuts in Emacs with a Bibtex file that you've created.
In the preamble make sure that you include:
Where you want the bibliography, type:
Replace <bibfile> with the full path to your Bibtex file. Don't include the .bib extension. (e.g. /User/user/bibfile)
Where you want to insert a cite type:
Then select the cite type from the list.
Then type the terms you want to search for and hit enter. A list will appear on the right. Select the reference you want and press enter.