The main interface is browser-based. You need to start an application in your computer, which then opens the browser page (and other computers, tablets and cellphones on your same network can go to that site as well).
As far as "support" goes, you can use Chrome, Firefox, Opera, Vivaldi, Edge, Safari, or anything you like. Some browsers sometimes change little things that may make some component in ERA look worse than in other browsers, but let us know if it happens and we'll see if we can do something about it.
If it's all the same to you and just want the best experience, your best bet would be using Opera or Chrome.
