I have one stata data file (say it is A) which is a survey data conducted in, say, 2000.
I also have data file (say it is B) which is a cumulative data set of survey conducted up to, say, 1999.
The both are differently organized so care must be given when putting the two files together.
So you have to read the description of each column, and then have to understand which column of A should be matched to which column of B.
Just two files. I think if you have ability, you can do it within at most 2 hours. (Printing part of the data into paper will let you see the relation between the two files more easily.)