Printing with pages on IPad using a non brother airprint printer

I have a brother printer that is not an AirPrint printer . I have the brother App for iPad that recognises the printer and it works however, I am unsure to go to ask it to look at the pages file I have created . Can anyone guide me through the process of creating a Test document and then I can save it to wherever it needs to go and then get the brother app ( IPrint&Scan) to find the file to enable me to print it . I did create a test one today but when I ask the app to look for it , it cannot find it ….any basic help would be appreciated kind regards

PS D o the files have to be in PDF or will any file option be ok ?