To create a duplicate python virtual environment, use

conda env create -f <file_name>

where <file_name> is either

1. gen_environment.yml (for easiest builds), or
2. environment.yml (for an exactly identical environment)

Most likely you should chose gen_environment.yml as it allows you to install the same python package versions immediately, but with python builds that anaconda thinks are appropriate for your system. In contrast, environment.yml provides the exact package build numbers used on my machine, which mean installing on a different platform will be difficult and will most likely fail.