A very novice question about ascii files

Hi all,
This is probably a very stupid question but I'm working on a really tight
deadline and I'm very confused.  I've got several incredibly hefty ascii
files that were at one point Oracle databases.  Now they're just plain
ascii dump files and today I got asked to put them in PGSQL but I have no
idea how (I've never even worked with databases before except for the
offline variety.)  Can anybody please point me towards some documentation
that would be helpful or give me some advice?
Thanks so much,
Leslie