You top at the 4th or 5th node,,,,when those have 3 or 4, you top the two and now you have 4 mains....
UB's topping thread is great info.....Hope you read it....
Don't take my first answer to heart,,,,,After many, many years of growing and then spending some years here. You start out trying to help and slowly you get kinda stir crazy at how many times some hot button topic that is a myth, misunderstood or just plain wrong is asked over and over again.....Yours was novel and I simply could not resist the temptation to have some fun.....
Yeah, we answer questions.....sometimes we get impatient with people who come on here and know nothing about growing and ask to have their hand held for 3-4 months while "they" grow and "we help".....All the time asking why this and why that is happening and how to stop it/fix the problem and half the time it's minor to nothing....
The best advice I can give now would be to have you get a house plant and read up on keeping house plants. Try an African Violet. If you can get that to bloom and stay healthy,,,you can be reading about growing MM while your learning to keep that African Violet alive and blooming....
Here, read these books very carefully. All of them! This will help keep you from asking awkward questions
Growing
Marijuana Grower's Handbook: Your Complete Guide for Medical and Personal Marijuana Cultivation: Ed Rosenthal, Tommy Chong: 9780932551467: Amazon.com: Books
More growing and it has a good section on room design and set up!
Marijuana Horticulture: The Indoor/Outdoor Medical Grower's Bible: Jorge Cervantes: 9781878823236: Amazon.com: Books
READ THIS to understand HOW plants and soil work = Organics
Teaming with Microbes: The Organic Gardener's Guide to the Soil Food Web, Revised Edition: Jeff Lowenfels, Wayne Lewis: 9781604691139: Amazon.com: Books
Now this one on Organic nutrition
Teaming with Nutrients: The Organic Gardener's Guide to Optimizing Plant Nutrition: Jeff Lowenfels: 9781604693140: Amazon.com: Books
Good Luck and ask if you need, anytime
Doc