Hello, Rock,
the simplest answer for your questions is Pages. If you hit Alt-T, the text dialogue opens up, showing your test/shapes. Position the cursor and click on the diamond button. This will place a page break at the cursor, giving you a second page to your file. Back in the main screen, the PageUp/PageDown keys will move you between pages.

Put your coin/medal into the second page, with a different face. When you run your spinning animation, Xara3d will spin the image once on the first page, then switch to the second page and spin the image on that. The switchover takes place while the shapes are edge on to the screen. Your coin/medal can have as many sides as you define pages for.

Mike