I know that there are many questions very similar to mine on this forum, but I still do not understand how my mistake can be fixed. Since I'm a novice with Latex and I wanted to create a bibliography for my document, I followed this step-by-step article by Overleaf about the use of biblatex. My problem is probably the creation of the file .bib: can I just open a new empty file Latex, write a code such as
@article{einstein,
author = "Albert Einstein",
title = "{Zur Elektrodynamik bewegter K{\"o}rper}. ({German})
[{On} the electrodynamics of moving bodies]",
journal = "Annalen der Physik",
volume = "322",
number = "10",
pages = "891--921",
year = "1905",
DOI = "http://dx.doi.org/10.1002/andp.19053221004",
keywords = "physics"
}
@book{dirac,
title = {The Principles of Quantum Mechanics},
author = {Paul Adrien Maurice Dirac},
isbn = {9780198520115},
series = {International series of monographs on physics},
year = {1981},
publisher = {Clarendon Press},
keywords = {physics}
}
@online{knuthwebsite,
author = "Donald Knuth",
title = "Knuth: Computers and Typesetting",
url = "http://www-cs-faculty.stanford.edu/~uno/abcde.html",
addendum = "(accessed: 01.09.2016)",
keywords = "latex,knuth"
}
@inbook{knuth-fa,
author = "Donald E. Knuth",
title = "Fundamental Algorithms",
publisher = "Addison-Wesley",
year = "1973",
chapter = "1.2",
keywords = "knuth,programming"
}
...
and save the file as a .bib document? After that, I tried to import my .bib file, which I called "sample", as follows:
\documentclass[12pt,a4paper]{article}
\usepackage[english]{babel}
\usepackage{biblatex}
\addbibresource{sample.bib}
\begin{document}
The Einstein's journal paper \cite{einstein} and the Dirac's
book \cite{dirac} are physics related items.
\printbibliography
\end{document}
The problem is that the .bib external file does not seem to be imported correctly. Indeed, when running the code Latex does not generate any bibliography, since the label {einstein}doesn't get associated to any number. How could I fix that? I'm sure that the way I created the .bib file is wrong, but apparently Latex does not point out the error. If I try to enter an undefined .bib file, such as \addbibresource{blabla.bib}, the output I get is exactly the same. What happened?

biblatexneeds in your case a run withbiberinsteadbibtex. Did you run biber? – Mensch May 01 '19 at 22:14biber, for example, orbibtexif you don't really needbiblatex. – Sigur May 01 '19 at 22:15backend=biberis the default. Other than that, did you run the normal cycle:pdflatex -> biber -> pdflatex (twice)? – Bernard May 01 '19 at 22:20backend=bibtexbut that is only to find out ifbibtexis compiling, better is to usebiberwithbiblatex... – Mensch May 01 '19 at 22:29.bblfile, that will be used in the second and third runs of LaTeX. Biber will produce a .log file (extension.bld) that you may look at to see if everything was OK. – Bernard May 01 '19 at 22:32