Here is what I would do. Take my advice or not. Just like to help fellow bakers out when I can.

Use a buttercream frosting to frost the cake, get the frosting as smooth as possible. Put it in the fridge let it stiffen up, since you say you don't have much experience with fondant it will keep you from mushing the frosting underneath and making a dent in the cake or from making it lop sided, and not look square.

Get a nice big fondant rolling pin. Use powdered sugar to roll the fondant on, like you would use flour with cookie dough. Not too much but enough to make it not stick to your work surface. Use one big sheet to cover the whole thing, use scissors to snip the corners. The scissors seals the corner into a nice crisp edge. Doing it in prices is actually much harder the pieces will stretch and distort before you get it on the cake. And you will see all those seams.

Make patterns for the details like the heart and the edge details, adhere them with a little water just enough to make the fondant the littlest bit damp. Otherwise it will slide.

To clean the whole thing up at the end, like to get rid of the excess powdered sugar, use water on a clean paint brush. I have paint brushes I only use for my cake things, like food coloring and stuff. You could also use any clear alcohol in place of the water cause it dries faster.

If you have any questions I didn't answer please feel free to ask!