Some people flush for a week some for a couple days. I personnaly flush for a day or two and then switch to bloom nutes. Some people reccomend to gradually scale back the light to 12/12 other jump straight into it. i just leave the light off for 24hrs and then go to 12/12. The flowering period, depending on the strain can be anywhere from 55 days to a lot longer. A good rule of thumb is to wait an extra week after you think it is done. Or just go by the trichs, but that requires a microscope. Oh and def do not take off all the fan leaves. Fan leaves store the nutrients that will be used in bud production later, thats why they die off towards the end of the flowering period. Most growers take off only the ones that are severly shading the bud sites. Just my 2 cents. Good luck bro...remember the plant will double in size during flowering.....