Orders is where you enter, store and manage all your sales orders and related documentation
Sub Total column is showing the total value inclusive of discount, before tax
Default Currency values are calculated using the rate set in Exchange Rates. See: General Settings - Seasons & Exchange Rates for more info
Select additional columns you want to include in your grid
Deselect the columns you don't want to see
Drag and drop columns to arrange them in your preferred order
Once you are happy with your layout, don't forget to save it so that in future you can make other temporary changes, then reload your favourite version.