The simplest for most users is to use the manager script of the TeX
installation to either install or upgrade mathastext to its current
version.

Else, download mathastext.dtx and follow these instructions:

- Run tex or etex on mathastext.dtx to generate the package style
  file mathastext.sty as well as additional files:

  mathastext.tex, README.md, ChangeLog.md, and some test files.

- Move the style file mathastext.sty to a location where TeX can
  find it. In a TDS compliant hierarchy this will be

      <TDS>:tex/latex/mathastext/mathastext.sty

For the documentation:

- Follow the above steps, then run latex thrice on mathastext.tex
  then dvipdfmx on mathastext.dvi. The file mathastext.tex can be
  customized to change the font size or set other options therein.
  The produced file mathastext.pdf will by default include the
  commented source code.

It is also possible to run pdflatex (thrice) directly on mathastext.dtx.
In that case mathastext.pdf is produced without the commented source code.

One can NOT use lualatex or xelatex to compile the documentation.

The test files

    mathastexttestmathversions.tex
    mathastexttestunicodemacos.tex
    mathastexttestunicodelinux.tex
    mathastexttestalphabets.tex

illustrate some features of the package and are an addendum to the
main documentation mathastext.pdf.