I am totally clueless about how this is done with my chief worry being that of my computer becoming messed up as a result of downloading things I do not fully understand. So I sought alternative solutions and in exploring China-Tools.com, I came across a pinyin editor on this website that does the job for me. It is not the best (the ideal would be to be able to highlight the pinyin sentences and get the intonation marks to appear at the click of a button or two) but it does the job well.
Just found this cool site that does the job just right -
zhē xiē nián yí gè rén
fēng yé guò yú yé zóǔ
yǒu guò leì yǒu guò cuò
hái jì dē jiān chí shèn mè