your doin the right thing with the light and 18/6.
As far as learning if male or female you will find that out after theve been put on the 12/12 light cycle for a week or 2 which you can do after about a month of veg(18/6)
you might wanna get yourself some bigger pots to transplant them into when there about 15-16 days old.
good luck :O)