In your DCA bot settings and in Deal start condition section click on the dropdown and select QFL

Then in the second dropdown you can choose which signal algorithm you like to use.

To help you decide you can check detailed QFL signal statistics from Altrady or also called CBS who is QFL signal provider for 3commas platform.

In the third cell you need to specify the percentage drop you like to get signal.

More about QFL signals described by 3commas https://help.3commas.io/en/articles/3108941-what-s-qfl