First, and separately, clone the original MashMap from https://github.com/marbl/MashMap and follow the instructions for installation there. As part of this, you will produce a Makefile suitable for your machine.
Second, clone this repository, https://github.com/medvedevgroup/MashMap, and copy the Makefile (from your installation of the original MashMap) into this directory. Then follow the remaining installation steps from the original MashMap.
A small change has been made in src/map/include/parseCmdArgs.hpp so that it will always set the window size to 1.