Microsoft has updated the Windows Insiders version of Edge Chromium Dev and added the ability to move your open tabs to a side bar instead of listing them horizontally across the top. Changing a settings in Edge gives you a button on the top bar which allows you to enable side tabs. Once enabled, there is an option to keep the left panel open or to minimize it depending on your preference. Although some development features never make to to the production version, this one's a sure bet to be released. Hopefully in the very near future.

For complete instructions and a walkthrough
watch the video below