The latest release is v1.0.0. Windows 7 and later should be supported - please file an issue if you have problems. Unfortunately, Windows XP is not supported.
Once you have completed the download, extract the zip archive to your preferred location, such as your Desktop.
Inside the folder, double click sulis.exe in order to launch the game.
You can configure the display mode, user interface scaling, animation speed and keybindings in the Options menu. This configuration is saved to Documents/My Games/Sulis/config.yml
This file also contains some additional configuration options not present in the UI.
There is a guide available for getting started playing the game.