Help! I made my first batch of no fail sugar cookies so that I could make a cookie bouquet for my mom (late mother's day gift) and it went horribly wrong.

I followed the recipe correctly.
Then I took the dough out from my KA mixer and kneaded it.
As I was kneading it, it just kept falling apart and crumbling.
I let it sit in the fridge for 2 hours (wrapped in saran)

I took it out and tried to roll it out... NO LUCK... it all just kept breaking apart and crumbling.

I managed to get a couple cookies cut. Put them on the cookie sheet and baked for 8-10 minutes.

I took them out. Waited. The cookies tasted HORRIBLE and were hard as a rock!...

This was my first time. So I wasn't even sure what to look for or what I was looking for! I didn't even get a chance to ice them, that's how bad they were.

Any help or suggestions would be appreciated.