Photographs

Select the photos together, that you want to print on one page. Then use the key combination ⌘P to open the print dialog. Now select al layout with two photos together or the contact sheet layout. For a contact sheet you can specify the number of columns and the width of the margins, you can also add tittles, dates, captions, or other metadata.

If you want more control, export them out of Photos and use Pages or the image processing program of your choice.