I'm doing my first wedding cake this week (due Saturday) but I have a couple of questions. First the cake that she wonts seems to be very simple (dont know how to post the picture) it's four layers 6 8 10 12. The 8 and the 12 are to be square, and the 6, and 10 round, all stacked. The 6 and 10 is t have small dots on the them, and the 8 and 12 is to have diffenent size circle on them, all the layers are to have a ribbon around them, but two layers are to have thin ribbon around it. The flavor will be pineapple, with buttercream filling crum coated with buttercream them fondant, with fondant accents. My question is should the ribbon be fondant, or satin, in the picture it was satin, but then I wuld need to know how do you make satin ribbon stick to fondant? Then I brought very small white balls (candy I think) from County Kitchen how do I make the stick. From looking at the cake the ball I brought is the ones that was n the cake.
I was also wondering if I should do two 2inch deep cake per layer (it will make 4inches) but once the fondant ging on it will be 3 inches, or should I do two 3 inch layer then the layer will be five inches after fondant goings on. The pictur I was looking at the cake look thick.

You know that an 8" square will overhang the 10" round? (geometry)

The standard height for wedding cakes is 4". Why would putting fondant on the tier make it 1" shorter? I don't understand that at all.

Be cure to uses SPS for support and take your paprerwork with you to the venue.

I was thinking the weight of the fondant would weigh it down

Your ribbon can be either satin or fondant, whatever you want to use. Just pipe a little bit of icing all the way around your cake where the ribbon will be and then put the ribbon over it and it will stick. If you choose to use satin, you should put Glad Press n Seal on the backside to make it food-safe.

As for the little white balls, you can paint a little extract on the back and it will stick to your fondant, but I'm not sure how little they are. HTH!

Is this a paying client or a friends wedding?

The fondant won't weigh down the cake an inch. In fact, it shouldn't weigh it down at all. Agreeing with Leah as well that a standard height wedding cake, each tier will be 4" tall.

To attach the balls, put a dot of royal icing on with a #1 tip and attach the ball with tweezers. Or you can water down fondant and paint a dot on the cake and carefully hold the ball there until it is secure, don't push it in to the fondant.

For the ribbon, go with satin, you can attach it using royal icing, just a couple of small dots around the cake will hold it in place, no need to make a whole line.

The fondant doesn't weigh the cake down.

4" is the standard US height, so your cake should be 2 x 2" layers + buttercream + fondant. Usually ends up being around the 4.5" mark once you have the coatings on there.

You really should address the overhang issue that Leah_s mentioned. The diagonal of an 8" square is 11.3" and your tier below that is only 10" wide, you've got an extra 1.3" there!

Luckly this is for a friend (free) but I still dont wont to mess it up, what do you think I should do about the layers of cake seeing the cake will over hang. What sizes should the cakes be

Did you create the cakes in your photos? One of them uses a ribbon, another uses dragees (which are similar to the white dots that you are asking about). Some of the cakes in your photos have been covered in fondant (so you would know that it doesn't crush cake) and the discrepency in cake pan sizing all have me wondering..