Maybe you do not know how to setup the plugin. 'Custom CSS' and 'Featured question ids' fields are looking empty because those are for you to fill. In 'Featured Question ids' you need to put the ID of a question which you want to feature. 'Custom CSS' field allows you to apply your own css so that your featured questions can look just the way you want but, you can also leave it empty if you wish to.
ID of a question is the 'number' which shows in URL of that question just after your website's name. For example the ID of this question is 53810 which you can see in URL above. You need to put ID of a question in 'Featured Question Ids' to make it featured.
If you want to uninstall the plugin then just delete the plugin folder in your qa-plugin folder in your hosting. To reinstall you need to upload this plugin to qa-plugin folder in your hosting and that's it.
I hope this helps.