\bibliography{bibfile} % The references information are stored in the file named "bibfile.bib"
\bibliographystyle{unsrt} % Set the style of bibliography as unsrt
In the body, use \cite{cite key} to cite a reference.
If the bibfile.bib is not in the same directory, relative path works. (e.g. ../bibfile , anotherfile/bibfile)
In order to make pdf with the bibliography,
1. Typeset with 'LaTeX' (input the commands), 2. Typeset with 'BibTeX' (input bibfile information), 3. Typeset with 'LuaLaTeX' (adapt citation information), 4. Typeset with 'LuaLaTeX' (sort the citations).