The steps below are for GitHub, but the steps are almost idential for Bitbucket, Heroku, etc.
Git uses a per-user config file located at
%USERPROFILE%\.gitconfig. Note that
git calls this config the "global" config. It's more general than per-repository config, and more specific than the machine config.
Download and run the MSI 'Windows Installer' from http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html