The only breeder i've purchased seeds from is Fastbuds. Great results so I continue to use them. I've never grown zkittlez, but i've ran plenty of Girl Scout Cookie as well as some Blue Dream, Gorilla Glue, Green Crack and Six Shooter. They are really easy to be honest.
1) Start them in their final pot so you dont have to mess with transplanting. Water the soil the night before planting. Soak it til you get runoff, plant the next day and you wont have to water for 7-10 days. Seriously.
2) Do not feed them until 28 days old. If you are using decent soil, they will be fine for the first 3-4 weeks.
3) Don't over water!!!! Biggest mistake of new growers.
4) Don't harvest early!!!! Post pics and we can help.