Add pointer to nice book for git newbies.

Author: astamm

site/guidelines-authors.qmd

@@ -63,6 +63,12 @@ These templates provide a starting point for authors to format their contributio
 
 ### Setup a git repository {#sec-git}
 
+::: {.callout-note title="Git and GitHub"}
+Git is a versioning tool and GitHub is an online platform owned by Microsoft which provides the service of hosting repositories with all the capabilities of versioning offered by Git.
+
+Computo requires authors to submit their contribution as a GitHub repository. Hence, authors are expected to have basic knowledge of Git. We refer authors to the following online book which is particularly well written: <https://happygitwithr.com>.
+:::
+
 Create a new GitHub repository by navigating to the [R](https://github.com/computorg/template-computo-R), [Python](https://github.com/computorg/template-computo-python), or [Julia](https://github.com/computorg/template-computo-julia) template repository and clicking the **"Use this template"** button at the top of the page, as shown in @fig-template.
 
 ![Screenshot of the R Computo template GitHub page.](/assets/img/computo-template-screenshot.png){#fig-template width="100%"}
@@ -71,7 +77,7 @@ Create a new GitHub repository by navigating to the [R](https://github.com/compu
 When you fork a GitHub repository – whether it is a classic repository or a template – GitHub will ask if you want to include all branches (there is a box labeled *Include all branches*). You only need to fork the main branch, so you do not need to check that box.
 :::
 
-::: {.callout-caution title="Public repository"}
+::: {.callout-caution title="Public/private repository"}
 The paper will be automatically published online using GitHub pages. This is possible only with public repositories (which is the default behavior when you initialize your repository from this template). It is  fine to keep your repository private during the writing phase. However, we ask you to set it public at the submission stage; so that the paper can be rendered and published online for the reviewers.
 :::