how can i design a slab and getting it's reinforcement details from staad pro.

The following post should be useful

http://communities.bentley.com/products/structural/structural_analysis___design/f/5932/p/99695/294596#294596

In addition, the page below contains lot of useful wikis on slab design and concrete design in general. The 7,8 14 etc. are specifically relevant for slab design

http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/2048.staad-pro-concrete-design-faq

The following post should be useful

http://communities.bentley.com/products/structural/structural_analysis___design/f/5932/p/99695/294596#294596

In addition, the page below contains lot of useful wikis on slab design and concrete design in general. The 7,8 14 etc. are specifically relevant for slab design

http://communities.bentley.com/products/structural/structural_analysis___design/w/structural_analysis_and_design__wiki/2048.staad-pro-concrete-design-faq