Nice plant! It's way too early to harvest if you want something reasonably good, your plant looks like it has at least another 3 weeks.
What does the weather look like for the next month? That will determine when you harvest, the later you can wait the better quality bud you will get, however you will also likely lose at least some produce to bud rot if the weather is wet, this is a balancing act.
For your harvest time, if you choose to put the plant in the dark for a day or two, you would do this while the plant is still in its pot.
Once you remove the branches from the plant, they will start their drying process, be sure you have your drying environment ready or they will go moldy within a short period of time.
Good luck!