Button on spawned window not being clicked nor captured

I have not used TestProject before so this is very much a learn as I go process. With the application I am testing the end task in the process requires a button to be clicked. This then causes a pop up window to appear which has another button on it which requires clicking to confirm that the action is to be executed. Although the test recognises the click on the first button on the main window, I am unable to get it to recognise that a new popup window has been created, which then prevents the test from then clicking on the ‘confirmation’ button this window contains. Could someone give me some ideas on how to get the test to recognise that the pop up window has ben created, and that there is a button on this window which has then been clicked.