FarmEx send attack to target every specified interval time. TradeEx doesn't work in order, so they aren't be affected by position of items in queue. FarmEx uses Raid as type of attack.
Interval is an integer representing the minutes, not representing the seconds.
Queue Items can be added by clicking on "+FarmEx" button of village's detail page. Click "Edit" to begin editing amount of units, then click "Check" to end editing.
You have to click Save button after adding items. Checking before save is necessary if you want to avoid mistakes.