If you are installing klipper for the first time, and have never used it, you will need to set a printer.cfg file that will tell klipper everything it needs to run on your machine. This is an excerpt from /doc/installation.md:
The Klipper configuration is stored in a text file on the Raspberry Pi. Take a look at the example config files in the config directory. The example.cfg file contains documentation on command parameters and it can also be used as an initial config file template. However, for most printers, one of the other config files may be a more concise starting point.
Arguably the easiest way to update the Klipper configuration file is to use a desktop editor that supports editing files over the "scp" and/or "sftp" protocols. There are freely available tools that support this (eg, Notepad++, WinSCP, and Cyberduck). Use one of the example config files as a starting point and save it as a file named "printer.cfg" in the home directory of the pi user (ie, /home/pi/printer.cfg).
Alternatively, one can also copy and edit the file directly on the Raspberry Pi via ssh - for example:cp ~/klipper/config/example.cfg ~/printer.cfgnano ~/printer.cfg
Make sure to review and update each setting that is appropriate for the hardware.
Once you have your printer.cfg file created and added to the home directory, add the following to your file.
[virtual_sdcard]path: /home/pi/sdcard[web_dwc2]## optional - defaulting to Klipperprinter_name: Reiner Calmund# optional - defaulting to 0.0.0.0listen_adress: 0.0.0.0# needed - use above 1024 as nonrootlisten_port: 4750# optional defaulting to dwc2/web. Its a folder relative to your virtual sdcard.web_path: dwc2/web