It is stated in the tasks' requirement that for IELTS Academic Writing Task 1, you should “summarise the information by selecting and reporting the main features, and make comparisons where relevant.” So, all candidates should write a very good overview/summary paragraph in your answer. It’s ok if you put summary either in the end of your report or straight after the introduction.
In your summary, you should select and report the main feature, which means you don’t need give all information in the chart(s) and you also shouldn’t mention any detail, which belongs to the detail paragraphs.
In addition, you don’t need a conclusion for your academic writing task 1. Conclusion is more like your final stance for an issue or any topic discussion. Academic task 1 is a scientific report, not an essay; therefore, you don’t need to give YOUR opinion, which means you don’t need a conclusion.