I have a fairly old version of FTM, so this may not work with your version. However I would expect there to be something similar available in your version. Also this procedure is based on a Windows PC/laptop rather than a Mac.
First of all check that you are in the view for the operation you want to print, so for instance, Descendant Tree mode etc. Then select the Print Setup option from the File drop down on the navigation bar at the top of the screen. This should open a dialog box based on your particular printer, and there you should be able to change the paper size to something like A3 if your printer supports that paper size. Obviously if your printer can't take the larger size paper you can't print on A3.
If you want to create a print file which would allow you to get the page printed on an external large printer, say at a print shop, select the Print [your choice] Tree option from the File drop down menu, and in the dialog box which appears, select Print to File from the right hand side. You will then be asked to name the file and select where it will be saved. Unless you have a preferred place for such files, you can select the media on which you want to transfer the file, such as a flash drive or memory stick etc. Failing that, use the desktop as it makes finding the print file at a later date easier.
