This setting is used for trailing stop-loss.
You need to first enable it by ticking EnableTrailingSL.
It will then start to trail after SLPipsDistanceToStart. It will keep moving the SL every SLTrailingPips by SLPipsAmount.
For example: if you set SLPipsDistanceToStart to 10, SLTrailingPips to 20 and SLPipsAmount to 5, it means:
EURUSD BUY at $1.23456
SL is initially set when price goes up to $1.23466. Then, when price goes up 20 pips to $1.23486, SL is moved by 5 pips to $1.23471