You can analyze results of your feedback button(s) in 2 sections. The first section is the "Dashboard" and the second section is de "Feedback" section. Both can be found in the left menu under "Button & Forms".
Analyzing one specific button in the Dashboard
When you are in the Dashboard you can select the button(s) in the top right corner to only display information of the selected button. By default the dashboard will display information gathered over the past 30 days from all your feedback buttons.
Analyzing one specific button in the Feedback section
When you are in the Feedback section you will see 2 panes appear. In the first pane located on the left you will find the filters. Filters can be used to filter the feedback items. At the top of the filter pane you will find the option to filter the feedback by buttons. When you click on this option you will see a dropdown which allows you to select one or multiple buttons. Additionally you are able to save the filter settings as a "Saved filter". The filters that you have applied will also be applied to any exports that you make with the filters active and the charts.
Keep in mind that in some cases you will not see all buttons because a button is not assigned to your Personal Usabilla account. The access to buttons is set in the "Team Settings" page which can be changed by your team-administrator.