Today we’re embarking on the next step in this journey – our first Canary and Developer builds are ready for download on Windows 10 PCs. Canary builds are preview builds that will be updated daily, while Developer builds are preview builds that will be updated weekly. Beta builds will come online in the future. Support for Mac and all supported versions of Windows will also come over time.
For more in depth information see What to expect in the new Microsoft Edge Insider Channels - Microsoft Edge Blog.
One nice aspect of the preview is if you already use Microsoft Edge, that existing version installed on your device(s) at this time will continue to work along side with the builds from any of the Microsoft Edge Insider Channels.