Pressing the camera icon at upper right should cause a Save As dialog to open. By default, this dialog saves to the Downloads folder. If you haven't used your Downloads folder before, you can find it with the Windows Search box.
The screenshot file will save with the name "screenshot.png" unless there is already a file by that name, in which case it will save as "screenshot (1).png".
The screenshot file will save with the name "screenshot.png" unless there is already a file by that name, in which case it will save as "screenshot (1).png".