Setting it at a distance of -20 pips, means that for this particular trade we won’t be losing more that.
Example EURUSD 1.4324 raise 10 pips will give 1.4334.
For buy trade, with stop loss of 100 pips, will give 1.4234.
For buy trade, with take profit of 50 pips, will give 1.4384.
Example GBPUSD 1.5882 drop 20 pips will give 1.5862.
For Sell trade, with stop loss of 80 pips, will give 1.5942.
For Sell trade, with take profit of 40 pips, will give 1.5822.