Building is very straightforward, you will need LaTeX and Git. The following command will create a local copy of the source code for you.
git clone https://github.com/anton-petrunin/invitation.git
Go to the created folder and run pdflatex and makeindex:
cd invitation/
pdflatex invitation.tex
makeindex invitation
pdflatex invitation.tex
If you want to use Springer's style, do
pdflatex invitation-springer.tex