how do you use a stoploss
You set your stop loss as a safety when you are sure and not sure about the direction a trade will go. If you are selling, your stop loss should be set above the point at which your trade was executed, so that your capital will be save if the trade buys instead of sells as predicted. If you are buying, stop loss should be set below the point of execution of the trade. The ability to be able to detect and correctly set up stop loss in each trade will help the trader ensure that they do not loose too much to a trade if it does not go as planned.
I think OP is asking how to set stop loss rather than when to set stop loss. Basically, OP is a newbie with no knowledge on how to set things up with the exchange he is using so he is asking us how to set a stop loss. I believe he doesn't have any experience in trading, so best for OP to learn is by doing it, trade with low margin and see things work. It is easier to learn things when you experience it, rather than merely reading replies from here or from google. And as a newbie, my friendly advice is to set a stop loss every time you position yourself in the market, don't trust yourself that you can monitor the market, sometimes it takes 30 seconds for the market to crash.