Begin by opening a PCPartPicker List. This can be accessed by clicking the Builder navigation button on their website.
Alternatively, if you already have a list you want to import, you can visit the page. The URL format for a list is as follows: https://pcpartpicker.com/list/XXXXXX, with XXXXXX representing six alphanumeric digits.
You'll want to click either the PCPP or Reddit markup buttons, in order to reach the Export Part List dialogue.
To finish, copy the code that is presented in the large text area, and paste it into the text area on this website.
Why Can't I Just Provide The List URL?
PCPartPicker prohibits the scraping of their website in their Terms of Service, and as they don't have a publicly accessible API, exporting the build list is the only way to get that information without needing to access their website from our end.