The screen scrolls past fairly quickly on a fast machine. You can stop and start it with Ctrl-s and Ctrl-q, respectively, and at the end of the run, you will get a list of any uninstalled packages.
It can happen that a package does not get installed because it depends on some other package that is listed for installation but is not yet installed. The answer here is to run Install again. Cases have been reported where it was necessary to run it four times before everything slipped into place. This will vary by your acquisition method.
Configure
Most packages get configured in step 3, but anything left hanging can be configured here.
Remove
Removes packages that are installed but no longer required.
Quit
I suggest running /etc/cron.daily/find at this point, because you have a lot of new files on your system. Then you can use locate to get the location of any given file.
3.20.3 A Few Hints in Conclusion
When the install process runs dselect for you, you will doubtless be eager to get Debian running as soon as possible. Well, please be prepared to take an hour or so to learn your way around and then get it right. When you enter the Select screen for the first time, don’t make any selections at all—just press Enter and see what dependency problems there are. Try fixing them. If you find yourself back at the main screen, run Select again.