When the user logs in their id should be stored in a session variable, usually called userID. there are several ways you can do this. One way is to modify the user authentication server behavior and add in the columns and names for the session variables that you want to set.
Another way you could do this is on any page that you would like to display info for that user you would need to add a recordset to the page, then filter it on the session variable for the userID. You can then just drag and drop these values onto the page where you would like to see them.
You could even have a page with a recordset on it that is filtered, then have a few set session server value server behaviors on the page to store this info in the session. You can then bind these session variables to any page or form that the user will see after logging in. The set session value server behavior should be present if you have eCart or Cookies toolkit installed.