SL is stop-loss - an order set at a price at which your position will be closed to prevent further loss. Always always use a SL. TP is a take profits order - an order set to close the position in profit and avoid any future loss of profit. Use a TP if your strategy and TA demand it. Use a TSL, trailing stop-loss, if appropriate to the strategy; this in some ways is a hybrid of both SL and TP as it could be triggered both in profit or in loss and stops price moving any further against you.