trend or forecast

I have done some research related to computer users and files generating pattern on PC. I collected data from PC where I have information when (date) , time, size of file, user, and file name. What I want to do is to divide this data into two groups, with first data set I want to find pattern for creation of files ( I need help with regard to what method is the most suitable). Second data set will be used for checking validity of prediction model.