Difference between a .bib and .bbl file for Latex

The .bib file format is used to describe bibliographical references. When used together with LaTeX and BibTeX, it generates a file with the .bbl extension, which is really just a tex file with a different extension containing your references formatted according to the bibliography style chosen in your .tex file through the \bibligraphystyle{} command. LaTeX then automatically inserts the contents of the bbl file in the exact place you call the \bibliography{} command in your document.

Usually, when working with TeX documents, journal and conference editors don't want to go to the trouble of using BibTeX to compile your paper; they prefer to defer the responsibility of sending the bibliography correctly formatted to the paper author (you). So, they tell you to manually do what pdflatex and bibtex automate for you: to get the contents of the bbl file and put them where you would call the \bibliography{} command. This way, you only have to send them a single tex file, instead of the tex file along with the bib file.

In texShop, you run Latex (Shift + Cmd + L), then Bibtex (Cmd + Shift + B), and then latex twice (Shift + Cmd + L), and you should be good to go with a bbl file and updated citations.

I'm sure the keyboard shortcuts vary between editors, but the process is roughly the same.

It's actually pretty easy. I'm sure you will enjoy using BibTeX for the rest of your life!

Here explains exactly how you do it: http://www.bibtex.org/Using/

Nevertheless, you can also use the program 'pdflatex' in your LaTeX code, and that's enough!

Editing: you don't actually have to read anything from the generated .bbl file. You only deal with .bib