I am trying to do a stencil transfer of a few lines of a poem on the side of my "practice" wedding cake. I have typed the lines in windows and printed the page. Do I need to transfer the print out of this to parchment paper or will tracing paper do??? also, what type of icing do I use to do this???? I so hope I am asking this question right...

What kind of icing on the cake? or is it fondant? If it's a crusting BC, you could lay the printout against the icing and trace with a toothpick so it makes impressions on the icing. Then pipe over.

Being my first trial run, I am using a buttercream frosting. I have always baked cakes and plenty of them just never actually decorated them so I'm very new at all this. So, any advice is appreciated!

If your buttercream forms a crust after sitting out, the above method will work. Or you can use the pinprick method, where you prick holes in all the letters beforehand, then smooth the back onto your crusted BC. If you are using a shortening BC that does not crust, it won't work.

You can do this on IMBC or SMBC if it has been refrigerated and is hard.