EmmaB Hey Emma, the information you need to input is as follows:
gourmetads.com, 15828, DIRECT
The certification authority ID is not explicitly provided in the ads.txt file you posted. The Certification Authority ID is optional, and many ad networks do not use it. If Gourmet Ads requires it, you would need to contact their support or check their documentation. It has allowed me to add it though so unless you see an issue with ads serving, it should be okay: