How to add data to shared excel sheet where it shows only the recent data

[Jkbytes]

Hi 

I'm having a situation where require to copy paste the data in a shared excel file 3 times a week and the other person updates "comment" column and the sheet needs to be checked for duplicates.  Once its get updated there should be a cell which should dynamically add the timestamp of the cell last updated

Please help

[#2]

cell which should dynamically add the timestamp of the cell last updated

track cell updated log ?
keep records of who when modify what values?