Stock Markets Exposed - how do i know when to sell or trade stocks when investing please give simple and best answer?

how do i know when to sell or trade stocks when investing please give simple and best answer?

do i go by market value? how do i know when to tranfer money from my stocks into my bank account?

You basically try to buy stocks when they are at a low price and you expect the price will rise. You sell them when you are comfortable with how much the price has risen (if it rises... there is always risk that it won't or will drop) and you will still make some money after fees, etc.
If you are buying individual stocks, you should have a business like reason for buying that stock...not a tip, not cause you heard a story in the news, but after analyzing a stock for it's intrinsic value and outlook for the future. So any way, no matter why you want to buy a stock, good reason or stupid reason....NEVER BUY A STOCK unless you HAVE A SALE PRICE IN MIND. A sale price means, what price do I sell to make a profit, and at what price do I sell to minimize a loss, If you don't have this figured out, you shouldn't be buying anything. If your stock takes a run upward, you can change your profit price, but you should also raise your selling on a downturn price accordingly. And not doing this causes more unnecessary losses for investors.