Press install from admin interface or upload files and activate as usual.
First you have to change the database structure to the one you need. Use PhpMyAdmin or any other tool to do so. By default this plugin creates ip_grid_widget table. But it is up to you. You can modify the table name and all fields in Config.php file. Make sure you reflect these changes in the database. Use PhpMyAdmin or any other tool to do so.
At the end, modify Plugin/GridWidget/Widget/GridWidget/skin/default.php file HTML to anything you like.
Here you have widget with custom management panel and look by changing just few lines of code.