Create a request by clicking on the plus button on the top left or the Create Request button on the welcome screen.
A dialog will appear. Enter a name and select a request method from the dropdown.
After creation the request view will be shown. Click on the input on the input at the top center and type in your desired URL. Click on the arrow symbol on the right of the input to send the request.
Afterwards you should see a new area right to your request view which shows the response from your request.