CircleCI deploy to AWS EC2

Question

I have/want a workflow like so:

1. Push branch to Bitbucket
2. Pull request branch into Master in Bitbucket
3. This triggers CircleCI to do a build
4. CircleCI deploys the successful build to AWS EC2 instance

I have steps 1-3 working but can't understand what syntax/files I need for the deployment step.

.circleci/config.yml

version: 2
jobs:
  - build:
      docker:
        - image: circleci/node:10.7
      steps:
        - checkout
        - restore_cache:
            keys:
              - v1-dependencies-{{ checksum "package.json" }}
              - v1-dependencies-
        - run:
            name: Install dependencies
            command: npm install
        - save_cache:
            key: v1-dependencies-{{ checksum "package.json" }}
            paths:
              - node_modules
        - run:
            name: Lint code
            command: npm run lint
        - run:
            name: Build app
            command: npm run build
        - save_cache:
            key: v1-build-{{ .Environment.CIRCLE_BRANCH }}-{{ .Environment.CIRCLE_SHA1 }}
            paths:
              - .next
  - deploy:
      requires:
        - build

workflows:
    version: 2
    build_and_deploy:
      jobs:
          - build
          - deploy:
              requires:
                  - build
              filters:
                  branches:
                      only:
                          - master

I have no idea what is meant to go in the deploy job so as you can see it's nearly empty. I can't find any examples of this online (I find plenty of S3 examples).

Should I somehow link to a deploy script? If so, I found an example that looks a little like this:

#!/bin/bash
BUILD_NUMBER=${CIRCLE_BUILD_NUM}
BRANC_NAME=${CIRCLE_BRANCH}
IMAGE_TAG=${CIRCLE_SHA1}

# Change to project root
cd ../

# Create an archive you make an archive
tar -zcvf project-name.tar.gz .next/

# Upload build to AWS
scp your_project_name.tar.gz ubuntu@your_instance_IP:/home/ubuntu

# Here you extract your archive on EC2 using SSH
ssh ubuntu@your_instance_IP tar -xvzf your_project_name.tar.gz

Can anyone help explain how this all pieces together?