What's in this directory?

These are files containing the installer and other software for the Debian GNU/Linux operating system. The files in this directory are specifically for the amd64 architecture.

How do I use these files?

The files here are bittorrent files. Use a bittorrent client program to download the contents of the complete ISO image files in a peer-to-peer manner. You should end up with an exact copy of each ISO image as though you'd downloaded it directly via HTTP or FTP.

Once you have downloaded all the ISO images you want, you will typically need to write them to installation media.

What size and type of media will I need?

The images described here are sized to be written to writeable DVD media at a minimum, but may be written to larger media if needed. For extra convenience, these images may also be written directly to a USB stick. So long as your computer will boot directly from that USB stick, it should start the Debian installer that way. The first DVD in this set is also deliberately limited in size so it should fit on a standard-sized 4GB USB stick.

There are lots of files here! Do I need all of them?

In most cases it is not necessary to download and use all of these images to be able to install Debian on your computer. Debian comes with a massive set of software packages, hence why it takes so many disks for a complete set. Most typical users only need a small subset of those software packages.

Initially, you will only need to download and use the first image of a set (labelled as debian-something-1 to be able to start the Debian installer and set up Debian on your computer. If there are more images available here (labelled debian-something-2, debian-something-3, etc.), they contain the extra packages that can be installed on a Debian system (as mentioned previously). They will not be bootable and are entirely optional. If you have a fast Internet connection, you're most likely better off installing any desired extra packages directly from the Debian mirrors on the Internet instead of by using these extra images.

How can I verify my download is correct and exactly what has been created by Debian?

There are files here (SHA1SUMS, SHA256SUMS, etc.) which contain checksums of the images. These checksum files are also signed - see SHA1SUMS.sign, SHA256SUMS.sign, etc. Once you've downloaded an image, you can check:

that its checksum matches that expected from the checksum file; and
that the checksum file has not been tampered with.

For more information about how to do these steps, read the verification guide.

Non-free Firmware

This is an official Debian image build and so only includes Free Software.

For convenience for some users, there is an alternative unofficial netinst CD build which includes non-free firmware for extra support for some awkward hardware. Look under /cdimage/unofficial/non-free/cd-including-firmware/ if you need that CD image instead.