Stop loss is selling the coin that we bought, when it drops to the point that we choose without caring about the loss. It is kind a stop the loss before lose too much. Stop loss is specified when the buyer buys the coin. Support and resistance lines are good assistants to specify the stop loss point. If you don’t know about support and resistance points, you can check this post to learn. https://steemit.com/cryptocurrency/@noproblem/awhat-are-the-support-and-the-resistance-points-how-are-they-used.
The stop loss point is 7-10% less than the point that you bought the coin. We see emotional behaviors usually, which stops people to sell the coin with loss and people hold the coin. After that the loss grows like topsy and people say that “I wish I sold the coin with less loss”. That’s why it is more important that knowing the time when you should sell is more important than knowing the time when you should buy. It does not only keep the loss minimum and close up the position but also realizes your profit. You can put a stop loss to a point to realize your profit and watch the coin. If it stops in your point you take your profit, If it increases more you will make more profit. Lets have a look on an example. 

Lets examine the REDD coin. We bought from the point 1 which is 78 and we put a stop loss on 70. It decreased in following days and our stop loss worked which sold the coin for 70. Lets look 5 days after than that. The price dropped to 42(you can see it on number 2). We sold it with 11% loss However ıf we did not sold it, we would have lose 85%!!! If it is not a long term investment, do not make any trade without stop loss! Trading without stop loss is like a suicide! So I think that you all are thinking about “how to use stop loss to realize the profit?” now. Let’s explain it with an example. 

We bought the coin from the point 4800 which we show with green line. After that the coin rises to 7000s and we think that will it rise more? At this time we put our stop loss to the point that we show which is 6000s. It realizes our profit. If it continues to rise we will change the place of our stop loss to higher points. However if it starts to decrease we will automatically sell it for 6000s. As you can see the price dropped to the points 5000s and we sold it from 6000s automatically.
How Do We Use The Stop Loss?
How Do We Use It On Bittrex?
We write the amount that we sell to the units part. Type should be conditional and you should choose “less than or equal to” for the sell when part. You write the price that when you want to start your stop loss to the part sell when. The price part is the price that your coins are sold. I mean in 70000 your stop loss works and sells your coins from 69050.
How Do We Use It On Poloniex?

Everything is as same as Bittrex but Poloniex has limit part as a price part and stop part is as same as sell when part in bittrex.
Please up vote this if you like and feel free to ask anything you want!