dselect runs through the entire set of packages and installs those
selected. Expect to be asked to make decisions as you go. It is
often useful to switch to a different shell to compare, say, an old
configuration with a new one. If the old file is conf.modules, the
new one will be conf.modules.dpkg-dist.
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.