Start feeding it approx. 3-4 weeks after it has popped through the soil. Give a light feeding at first so you don't burn/overfeed your plant. I suggest using only 1/4 strength at first, feeding once a week, then slowly increasing to 1/2 strength, 3/4, then full strength.

30-10-10 is fine for the vegging stage, the stage you are in now, but when flowering time comes, you want something high in P (N-P-K), like 10-15-10, or 15-30-15, something along those lines.

Good luck and welcome.