Once you install it open new tab and click on Profile icon and then it will take you to extension option from here you can change Name, Color, Animation, add custom CSS, import or export tile list, setup weather app.
You can add new tile too, just click on profile and then click on Add Tile, then it will ask for details, just enter it , if you had logo then you can add it otherwise it will fetch logo itself.
You can also change position of any tile, just drag and drop it, You can also change size of tile by just right clicking on it and you will see options at bottom.
I had used it and liked it very much, it gives you nice feeling of metro UI and of Windows 8. If you have to say anything about it then please share it in comments section.