The best and the most simple way to do this is to use the conda package management system. You can get it very easily from the Bioconda channel and install Neptune from there. However, most critics recommend using the Miniconda. The best way that is recommended by the critics as well would be to combine both bioconda alongside miniconda. This works perfectly most of the time. This is because Minoconda has two Python installers 2.7 and 3.6 and both work very well with the Bioconda software application.