How to place stoploss order for holding stock for long period

Hi. Please, any one explains how to place/maintain stoploss sell order for portfolio stock over unlimited days irrespective in case we unable to access the market for some days.

Good Till Cancelled Orders are Currently not available on Zerodha Trading Platforms.

Download a third party app and create a Stock Price alert Function to remind you when the price hits your target.

Please, will you tell which 3rd party app to download and how it will help to trigger order automatically in our absence from the market?