login issues...very lost....

I just started learning how to use php with dreamweaver and i figured out ho
w to use the user authorization/user login in.  I also made a sign up page w
hich enters people’s information into a table that has their usernames and p
asswords stored.  But how do I set up the php so when a specific user logs i
n it will redirect them to their personal update page? I have a general idea
 of foreign keys but still don’t fully understand if I should use them for s
omething like this?