If you want to get a high score for task 1, you must write an 'overview' of the information. An overview is a summary of the main points or general trends.
How would you write an overview for this graph?
I try to write two sentences for my overview, so I look for two main points or trends. I don't usually mention any numbers because I save them for my 'details' paragraphs.
It is clear that Canada exported more wheat than Australia and the European Community for most of the period shown. However, while Canada's wheat exports fluctuated and Australia's fell, wheat exports from the European Community rose steadily.