writing an article, 2400 words , the title is A critical analysis of laser bleaching, the spacing max 1.5 in between lines / lettertype Arial or Times New Roman / fontsize max 12 i need to see these sub headings the article is about A critical analysis

 writing an article, 2400 words , the title is A critical analysis of laser bleaching, the spacing max 1.5 in between lines / lettertype Arial or Times New Roman / fontsize max 12

i need to see these sub headings 

the article is about A critical analysis of laser bleaching( in dentistry )

includes;

abstract

- introduction

- Material & methods (= literature search)

- results

- discussion (your comments regarding the results)
- conclusion

references