May I know if you are actually looking at the installation of Mattermost Server or rather the desktop / web app itself?
If you are looking at Mattermost Server, only Linux / Kubernetes Bitnami / Docker deployments are available as mentioned in Installing Mattermost documentation. No specific Windows installation guide available.
If you are referring to the installation of the desktop app, please refer to the Desktop Application Install Guides instead which includes a Windows guide for 7, 8, 10.
Sorry for the late reply, I just stumbled upon your question. if this is still relevant for you, please create a new topic and provide some more details (like what are you trying to achieve, f.ex.).