This step pertains to sites hacked to host spam, often with the warning "This site may be hacked" displayed in search results. It's one of the longest steps in the recovery process. In this step, you'll compile a list of the damaged files on your site. You'll use this list in a later step, Clean and maintain your site.
If your site was affected by malware and is flagged with the warning "This site may harm your computer" in search results, please see the corresponding article, Assess malware damage (Hacked with malware).
The next step in the process is Identify the vulnerability.