I have provided a utility to let you import existing "people" from a CSV (comma separated values) formatted file. This is just a matter of browsing to the .csv file that has the data you want to import and then dragging and drops the columns on the left side to the corresponding column on the right.
The process may be easier if your .csv files has a header row with field names. However, if you do not uncheck the Strip Header Record check box you may wind up with an extra record that has values like "Customer", "Company" etc.