The instructions below outline how to open and close positions on both the desktop and mobile versions of MT4/MT5.
 

On MT4/MT5 (PC)

To open a position:

1.  In the Market Watch window, double-click the instrument you want to trade.
2.  In the pop-up window, select your instrument.
3. Configure your execution type, volume and SL/TP where applicable.  
4. Tap "Sell by Market" or "Buy by Market" to execute the trade.
   

To close a position:

1. Go to the Trade tab.
2. Right-click on the position you want to manage.
3. Click "Close Position" to immediately close the position at the current market price.

On MT4/MT5 (Mobile)

To open a position:

1. Go to the Quotes tab and tap the instrument you want to trade,
2. From the pop-up menu, select Trade (iOS) or New Order (Android).
3. Configure your execution type, volume and SL/TP where applicable.
4. Tap "Sell by Market" or "Buy by Market" to execute the trade.
   

To close a position:

1. Go to the Trade tab.
2. Tap and hold your finger on the position you want to manage.
3. Select "Close position". 
4. Tap the wide yellow/orange button at the bottom that reads Close with Profit/Loss [Amount].