Dear Anas Anis,
having the DHTFilesharingResults.csv is a good start. Now you just
have to plot the results.
Gnuplot offers a good tutorial on how to be used: http://gnuplot.info/docs_4.4/gnuplot.pdf
First of all, you have to open the .plt files, look into it and
understand how gnuplot works.
After that, you can also use the gnuplot-file listed on the seminars