In this video I am going to walk you through installing Sitecore Experience Commerce 9 Update 1. Previously in one of our Unofficial Sitecore Training, we went through installing Sitecore 9 using SIF. You can view the videos on the Our Core Community site.
A base Sitecore 9 install is one of the pre-requisites for the commerce install.
If you have any questions or concerns, please get in touch with me. (@akshaysura13 on twitter or on Slack).