How do I do this? I'd imagine if you lay cupcakes side by side that there would be gaps because they're round. I read somewhere in the forum there is a thread that discusses this but I can't seem to find it.

Can anyone explain how to do this or share a link to that thread in question?

Would really appreciate it

look for threads about cupcake cakes. very easy really, secure the cakes to a board (some use different icing, some a cocktail stick), and ice over the whole thing - the icing fills in any gaps.
xx

You can put large marshmallows in between the cupcakes to fill in the gaps before you place the icing on it. I made a cupcake cake the other day for a paraprofessional's birthday. It won't have straight sides, but that's adds to the charm of a cupcake cake. I use a large spatula to spread the top coat, and I use Viva paper towels to smooth the icing after it crusts over. Then I decorate it just like a regular sheetcake. I hope this helps. You can email me if you need any more information.

I glue mine down with royal icing then fill I did a confirmation cake last week that way I made it into the shape of a cross. Don't be afraid it's not as bad as it seems.

Here's a fairly recent thread on how to make a cupcake cake.
HTH

http://cakecentral.com/cake-decorating-ftopicp-6778631-.html#6778631