Clarify GitHub install procedure (plk#741)

Author: moewew

README.md

@@ -5,27 +5,27 @@ This package provides advanced bibliographic facilities for use with LaTeX.
 The package is a complete reimplementation of the bibliographic facilities
 provided by LaTeX. A custom backend Biber is used by default which
 processes BibTeX format data files and them performs all sorting, label
-generation (and a great deal more). 
+generation (and a great deal more).
 
 Biblatex does not use the backend to
 format the bibliography information as with traditional BibTeX: instead of
 being implemented in BibTeX style files, the formatting of the bibliography
-is entirely controlled by TeX macros. 
+is entirely controlled by TeX macros.
 
 This package supports subdivided
 bibliographies, multiple bibliographies within one document with different
 sorting, separate lists of bibliographic information such as abbreviations
-of various fields. 
+of various fields.
 Bibliographies may be subdivided into parts and / or
-segmented by topics. 
+segmented by topics.
 
 Just like the bibliography styles, all citation
-commands may be freely defined. 
+commands may be freely defined.
 
 With Biber as the backend, features such
 as customisable sorting, multiple bibliographies with different sorting,
 customisable labels, dynamic data modification and custom data models are
-available. 
+available.
 
 The package is completely localised and can interface with
 the Babel and Polyglossia packages. Read below for how to
@@ -50,7 +50,8 @@ This work has the LPPL maintenance status "maintained".
 
 # Installation
 
-biblatex is bundled with TeXLive and its variants.
+biblatex is bundled with TeXLive and its variants as well as MikTeX.
+Normally you can install and update biblatex through your TeX distribution.
 
 biblatex starts life on Github where you can always find development
 releases:
@@ -68,29 +69,44 @@ get the latest stable version:
 
 [https://ctan.org/pkg/biblatex](https://ctan.org/pkg/biblatex)
 
-Installation from github
+## Installation from github
 
 For this you'll need to be on a UNIX-like system (use
 [https://www.cygwin.com](cygwin) on Windows) that has bash and perl.
 
-First clone the repo:
-
-`git clone https://github.com/plk/biblatex.git`
+You should only install from github if you want to check out the bleeding edge
+of development or if there is absolutely no way to obtain either the official
+historical releases from
+[SourceForge](https://sourceforge.net/projects/biblatex/files/) 
+or the current release from [CTAN](https://www.ctan.org/pkg/biblatex).
+Remember that you will need a matching Biber version (the binaries are
+distributed on [SourceForge](https://sourceforge.net/projects/biblatex-biber/files/biblatex-biber/)).
 
+First clone the repo:
+```
+git clone https://github.com/plk/biblatex.git
+```
 Then from the clone root:
-
-`obuild/build.sh install <version> <texmf root>`
-
+```
+obuild/build.sh install <version> <texmf root>
+```
 for example, say the currently released version is 3.3 and you want to try
 the 3.4 development version. Suppose your personal texmf root is at
 `~/texmf`:
-
-`obuild/build.sh install 3.4 ~/texmf`
-
+```
+obuild/build.sh install 3.4 ~/texmf
+```
 If this is the first time you are installing `biblatex` into `~/texmf`, you will have
 to tell TeX that it can find the files in this new location with `texhash`
 or the equivalent command from your TeX distribution.
 
+Note that the install script does not fetch and install the official biblatex
+release version corresponding to the version argument supplied. It just takes
+the files that are currently checked out, moves them and changes their version
+identifications so that they identify as the version given in the argument.
+If you want a specific version, you must check out the corresponding tag or
+obtain the corresponding sources otherwise before running the script.
+
 Obviously, its is easier to get the TDS format package from the Sourceforge
 development folder and just unpack it into your `~/texmf` but this might
 not be quite as recent as the git development branch (but is usually very
@@ -134,5 +150,5 @@ Suggestions and bug reports are welcome.
 
 - Go to the Github [issues page](https://github.com/plk/biblatex/issues).
 - Open an issue.
-- Add a [minimal working  example](http://www.tex.ac.uk/cgi-bin/texfaq2html?label=minxampl) if
+- Add a [minimal working example](http://www.tex.ac.uk/cgi-bin/texfaq2html?label=minxampl) if
   possible. This helps a great deal facilitate a swift response.