There are lots of good guides, just do a search for 'cloning'
And you won't know the sex until you bring the light cycle to 12-12, so if you do so beforehand from normal seeds, you may be cloning a male (ie: dont do it). You can clone a flowering plant however fine.
Typically, you don't clone a plant until the gender is known.
Some plants will "preflower" once they become sexually mature, showing single flowers at stem/leaf nodes to indicate the gender before actually flowering. That's a good clue, if it happens.
If not, you run the plants 12-12 until the declare gender, THEN clone. (Its OK to switch back to vegetative growth, if you like).
Note that if you are breeding there are SOME circumstances where you might want to clone males, and that, of course, can be done just like females.