Any ideas on how to create a flat level square cake. I tried and it looked more like a circle when I was done with it : ( Any advice would be appreciated : )

Not quite understanding what you mean. How are you getting a circle? I'm assuming you're baking in a square cake pan, right?...to level just trim the top.
However, if there's a crater in the cake that makes it uneven, I've used cake trimmings mixed with BC to fill in and level the top. Refrigerate until firm and then frost it.

I am using a square pan, when I frost the cake somehow I don't get the smooth edges.

This happened to me once! I realized I was putting too much frosting on the cake. So when I made the new one I put a really thin layer of frosting then put it in the freezer until it was firm (about 15 min) then I put a second layer.... I think its called dirty icing the cake...

I layer my frosting on as well. Crumb coat first, then cool, (not freeze...it doesn't need to be frozen, just really cold) then first layer smoothed on, cool, etc., etc., until you can't see cake.

Are you using a bench scraper or a trowel? If not, get one. You'll get really smooth sides and if you bring your frosting a little past the edge of your cake when you're swiping it, then you can turn the corner and bring it in with your scraper and get the sharp edge.

Another trick is to let your buttercream cake come to room temp and while it is crusted but soft underneath, take a foam sponge roller and lightly roll over your cake and you can smooth out lumps and shape corners too. Some people use the Viva towel method too, but so far, I like the roller best when I need to do it.

If you need to see some tutorials, just go to YouTube and put in something like 'How to frost a square cake with buttercream" and you'll have a bunch of them come up. Good luck!