Each of the above access methods will at some point ask for the location of the ``top level'' of the distribution. If the archive is in the ``standard'' form, pointing to this ``top level'' will be all that is necessary. dselect will find a Packages file for the binary-i386 portion of the distribution as well as contrib, and non-free. The path to the local distribution will be asked for separately, as well as any of the above that were not found in the ``top level''.
If the distribution is in a nonstandard layout, dselect will notice this and complain that what was identified was not, in fact, the ``top level''. In this case simply answer ``none'' and each section will be prompted for separately. Note: Switching VCs (see below) will allow an investigation of the distribution archive so that the path to binary-i386 can be found as well as contrib and non-free.
Note: The Virtual Console (VC) is a method for sharing the console monitor with more than one login process. Debian configures six Virtual Consoles. The left ALT key pressed along with a function key (F1 thru F6) will place the corresponding session on the monitor. It's like having 6 separate terminals!
In addition to the three ``standard'' distribution collections, dselect offers the option of giving the location of the ``local-distribution''. This local distribution is for use at the direction of the local system administrator. Packages that have been created as .deb package files that are not available from the Debian archives are candidates for placement in the local archive. Although alternate packages that do exist in the archive can go here, the Packages file for the local archive must be ``merged'' by hand using dpkg --merge-avail before dselect will recognize them for installation. This is because dselect is unwilling to downgrade a package, so those packages must be the only ones in the available file for proper installation. If the intent is to operate in this fashion then the update of available will need to be done by hand and the ``Updated Available file'' option should not be executed.