How to edit the Bibliography style using BibLatex and a .bib exterior file, in Overleaf?

Question

I really don't know how to edit the style.

I was following this post Guidelines for customizing biblatex styles which has the concerns that I have but got stock in its answer in the

I recommend to use the configuration file biblatex.cfg. This file, if available, is read by biblatex immediately after a style has been loaded. The (empty) original is located at /tex/latex/biblatex in your TeX distribution directory; put a copy in the analogous location of your local TEXMF tree (and update your file database) and fill it with the redefinitions I'm (finally!) going to talk about.

part. Ideally, or what was I doing so far was just adding a predefined style from the Overleaf Bib styles page but it doesn't have the style I am required to have. The closest are the ieee and chem-angew styles. Can they be modified somehow?

What I'd like is

[#] Initial letter of the name(s) followed by their 1 or 2 last names, "title of the paper", magazine, vol., no., (year) page-page

[#] Initial letter of the name(s) followed by their 1 or 2 last names, name of the book, edition, publisher, (year).

And when citing the [#] appearing.

Answer 1

Before we start, a word of warning: If this style is for a submission of a paper to a journal or a publisher, biblatex might not be your best bet. Very often publishers have their own templates that come with a BibTeX style or at least with instructions how to generate the bibliography. Generally, publishers do not accept biblatex submissions. (See also Biblatex: submitting to a journal)

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Most biblatex style modifications can be made directly in the preamble of your document. Indeed, all modifications that can be made in biblatex.cfg can be made in the preamble and vice versa. Since biblatex.cfg is easily forgotten about, I usually recommend people just write their modifications to the document preamble.

It is possible to use biblatex.cfg also on Overleaf: Create a new blank file called biblatex.cfg by clicking on the "New File" icon on the top left. Then just add your biblatex modifications there. See for example https://www.overleaf.com/read/cbcnvhhbmdwx.

But as I mentioned above, I don't think this is necessarily the best way forward.

Here is a start for your style with the modifications directly in the preamble.

\documentclass[english]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}
\usepackage[backend=biber,
  style=ext-numeric,
  giveninits=true,
  articlein=false,
]{biblatex}
\renewcommand*{\newunitpunct}{\addcomma\space}
\renewcommand*{\volnumdelim}{\addcomma\space}
\renewcommand*{\bibpagespunct}{%
  \ifentrytype{article}
    {\addspace}
    {\addcomma\space}%
}
\DeclareFieldFormat{date}{\mkbibparens{#1}}
\DeclareFieldFormat[article,periodical]{date}{#1}
\addbibresource{biblatex-examples.bib}
\begin{document}
Lorem \autocite{sigfridsson,nussbaum,companion}
\printbibliography
\end{document}

I used a biblatex-ext style to make some of the modifications even easier than in standard biblatex. You can find more details about this in the biblatex-ext documentation.