npm install -g @aws-amplify/cli

amplify configure

amplify init

$ amplify init
Note: It is recommended to run this command from the root of your app directory
? Enter a name for the project nextsampleapp
? Initialize the project with the above configuration? No <- おすすめのままではだめ
? Enter a name for the environment dev
? Choose your default editor: Visual Studio Code
? Choose the type of app that you're building javascript
Please tell us about your project
? What javascript framework are you using react
? Source Directory Path:  src
? Distribution Directory Path: .next  // <- 最重要
? Build Command:  npm run-script build
? Start Command: npm run-script start
Using default provider  awscloudformation
? Select the authentication method you want to use: AWS profile　// ここはご自身の環境に合わせてください

amplify add hosting

$ amplify add hosting
? Select the plugin module to execute Hosting with Amplify Console (Managed hosting with custom domains, Continuous deployment) //Amplifyが作るものを利用する
? Choose a type Continuous deployment (Git-based deployments)
? Continuous deployment is configured in the Amplify Console. Please hit enter once you connect your repository