How do I install DC++?

Just run the installer and fire up DC++, then enter the settings to set it up according to your preferences (most important is nick, download location and shared folders).
You can also download the .zip file and unpack it.

How do I uninstall DC++?

Use the uninstaller that followed when you used the installer.
If you didn't use the installer: You can delete your DC++ folder, but be aware that dchub://, adc:// and magnet: will remain in the registry. If you disable Register with Windows to Handle dchub:// and adc:// URL Links and Register with Windows to Handle manget: URI Links, these registry settings will be removed.

How do I upgrade DC++?

Just install in the folder your old version was in. Your old settings will still be there.

BEWARE: Old (ver <= 0.163) Notepad notes will get lost, format change in 0.17
BEWARE: If you upgrade to 0.22, all old queue items that are missing a directory in the target file-name will be removed. Don't upgrade if your queue is precious to you, and you didn't have anything in the default download directory box in the settings (finish it with version 0.181 or edit your queue.xml file and add a directory to all targets without...).
BEWARE: If you upgrade to 0.4033, all logs will be formatted as UFT-8 (Unicode), instead of ASCII.