Yeah, whatever you do, don't over water!! Everyone does it starting out, and it can lock out nitrogen, plus basically completely stall their growth. Take it from me, you don't want to get set back that early on, it sucks.
Make sure you have good drainage holes. You'll be glad you added the extra perlite. As long as it drains well, you can't over water with one watering, just get used to feeling how heavy the pot is when its just been watered, and when it loses 50% of its weight you water again.