Basically playing the forex is to predict a currency pair to rise or fall in value. And the confidence of the predictions that we achieve in open position / trade. And in forex there are only two kinds of open positions. Namely
1. BUY / BUY / LONG: predicting value pair INCREASED
2. SELL / SELL / SHORT: predicting value pair DOWN

In order to be clearer, see the illustration below.

1. Handoko entrance in a position to BUY EUR / USD at 1.3000, after a certain time
Handoko SELL (CLOSE) at 1.3064 then Handoko gain profit 64 pips / point (the smallest unit in forex).

If Handoko SELL (CLOSE) in 1250, Handoko suffered a loss of 50 pips

2. Erik entered in positions SELL GBP / USD in 1500, after a certain time
Erik BUY (CLOSE) in 1400 then Erik gain 100 pips / points (the smallest unit in forex).
If Erik BUY (CLOSE) in 1650 then Erik loses 150 pips

Note, if you look in the application:
* Rates are used when OPEN BUY / LONG is the purchase price (ASK) and the prices used when you close / liquid is the selling price (BID).
* Rates are used when OPEN SELL / SHORT is the selling price (BID) and the prices used when you close / liquid is the purchase price (ASK).