Dear Mr. Umair Nisar

Here I attach a file that can guide you to do rietveld refinement using softwares.

Thanks Putu Tedy for the files, apart from guide on how to perform rietveld refinement, I am also interested in basic understanding about rietveld analysis i.e. theoretically understand what information can we get about crystal structural using rietveld analysis etc. 

If you search google little bit, you can find many of them, e.g. here:

Detailed: http://struktur.kemi.dtu.dk/kenny/Rietveld_Compendium.pdf

for a quick look:

http://home.wxs.nl/~rietv025/

http://navrotsky.engr.ucdavis.edu/pages/classes/2006ClassArchive/ECH289J_Winter06/class_docs/ech289j-wi06-lect6-rietveld.pdf

http://www.ing.unitn.it/~luttero/laboratoriomateriali/RietveldRefinements.pdf

Thanks for sharing the links, yes I agree when you google can help a lot, but sometimes other people base on their experience can directly recommend the best of them :)