when to plant seeds?

I have 3 autoflower seeds. I placed them in moist paper towels between 2 plates. I then placed them on my cable box yesterday. They all started to crack open today. I was wanting to know when should I plant them in soil? Should I plant them now or wait another day for the tap root to get alittle longer? Or should I place them in my root riot cubes now?

Put them in before they pop, after they pop what ever.
autos do not like to be transplanted so put them in the pot they will be in the whole grow.