Example of using custom handler with serverless-next.js component

I am using GitHub - serverless-nextjs/serverless-next.js: ⚡ Deploy your Next.js apps on AWS Lambda@Edge via Serverless Components and don’t see an example of using a custom handler instead of the default handler.

Can someone point me to example code? Apologies if this is not the right place to ask the question. Please point me to the right forum so I don’t keep posting in the wrong place.