Deploy infrastructure (Cognito User Pool, CloudFront Distribution, S3 Bucket) :
sam deploy --guided
Then grab your User Pool id and User Pool Client Id and modify the file awsexports.js with these values
Then you can start the app in local mode:
npm run start
Build the app to generate your static website
npm run build
Sync the static website to your s3 bucket
aws s3 sync build s3://your-s3-bucket-name