The specific steps of how to find his complaint letter when the other party goes to the platform of Guangdong Education Reporting Network are as follows:

1. Enter the website of Guangdong Education News.

2. Select "Petition Inquiry" in the navigation bar at the top of the home page.

3. On the inquiry page of letters and visits, select "Inquiry Method" as "Complainant's Name" and enter the name of the other party.

4. In the following query criteria, select "Complaint Time" and enter the time range of the other party's complaint (if any).

5. Click the "Query" button, and the system will list the qualified complaint letters.

6. In the complaint letter list, find the letter complained by the other party and click the "View" button to view the details of the letter.