On the bottom of your screen, tap on "Portfolio" tab

Click on "Modify" of the Trade you wish to close, to open the “Modify” screen.

Tap on “Close Trade” and then select “Yes”

Find your closed trades and check your history by following the below steps:

Select the "Portfolio" Tab

Tap on "Trade History"

You may choose the time period of closed trades (slide to the far right for All Trades)