1. If its in a container, water when it needs it. Could be twice a day could be twice a month. make sure the soil never dries completely out.
2. Once it gets good and established start it out at 1/4 strenght and work you way up to full strenght.
3.Walmart, Ace hardware.. plant stores... internet..
4.You can top it(cut the stem) once it gets about 7 sets of leaves. This will make it grow bushy instead of tall. You can also simply lay it over when it gets big.
5.Cannabis grows like a weed. Just make it happy. Outdoor growing is easy. Just let it grow. Watch for pest, White flies and aphids are evil.