In essence, postcards are labels from the Word point of view.

To set up the postcard /layout/, you can try setting the merge up as a label
merge and either selecting the correct label format for your cards or
defining it.

To set up the postcard /content/,  put the merge fields you want into the
first card, and when they are laid out how you want and properly tested,
copy them into the other 3 cards. Then make sure that there is a <<Next
record>> (i.e. { NEXT }) field at the beginning of cards 2,3, and 4 (but not
card 1).

If that doesn't help, can you state
a. exactly which part of the merge you are having difficulty with
b. whether or not you are trying to print double sided cards (it's
different)
c. which version of Word, and what type of data source you are using (Word,
Excel, Access etc.)

Peter Jamieson

postcards should be treated as mailing labels -
http://www.gmayor.com/mail_merge_labels_with_word_xp.htm