Walkmaker concrete form question

I am planning on making a 20 ft x 4 ft front pathway using a Euro Block Pattern mold. I have a couple questions for those who have experience with this product:
1) The instructions say I can just lay this on a dirt base, is that true or should I lay a sand base. I live in the Midwest where temps can get to -10.
2) The instructions say I can use regular concrete or they recommend fiber reinforced concrete. Since fiber is more expensive, is it really worth it?
3) Any comments on people using this product? Did you like it? Any special techniques when laying it?
Thanks, John

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