Offline installation for Python Packages

Hi,

I am perfoming an offline install for python extension: Create a New Python based KNIME Extension

Step 5: On the target offline system set the environment variable KNIME_PYTHON_PACKAGE_REPO_URL to the folder with the downloaded packages.

I dont really know where to set the environment variable KNIMEPYTHONPACKAGEREPOURL can come anyone share a screenshot of where to set this? Thanks!