I have never used straws for support. Not even sure how or when it is necessary. I have only made double 6 and 8's stacked and have'nt needed them. I am now doing double 6, 8 and 10 for my daughter's cake. The top 6 has filling. Do I need them, where do they go? Any suggestions greatly appreciated!!!

What have you used for support before? You need them for support so cake doesn't squish itself under it's own weight. The straws go between tiers. Search the forum for stacking cakes and you will find lots of stuff.