Stop-loss market (SL-M) order is similar to a stop loss order, where your order will get triggered when “trigger price” is hit in the market, however in SLM the order gets executed at the market price.
 

You can add a stop loss to your regular order 
Step 1: Click on Buy/ Sell to open the order pad of the desired security

Step 2: In the top navigation pane, click on "Regular order"

Step 3: Enter the quantity and the price. (The market price is automatically selected, if you want to place a limit order, click on "Custom Price" and enter the price. You can also choose the price from market depth)

Step 4: Click on advanced options, and on SLM (Stop Loss Market order) Enter the stop loss trigger price

Step 5: Click on Buy / Sell to place the order

Step 6:  If you have set up a review screen, you will need to confirm the order before it gets sent to the exchange.