https://blog.chapimenge.com/posts/serverless/todo-api-serverless/ with DynamoDB added serverless.yml

serverless.yml

service: Todo
frameworkVersion: '3'

# new
custom:
  tableName: 'todo-table-${self:provider.stage}'

provider:
  name: aws
  runtime: python3.8

  # Totally optional, but it's a good idea to set this
  stage: dev
  profile: default # if you are working with different AWS account
  stackName: todo-stack
  logRetentionInDays: 14
  region: 'us-east-1' # if you are working with different AWS region choose nearest to you

  # new
  iam:
    role:
      statements:
        - Effect: Allow
          Action:
            - dynamodb:Query
            - dynamodb:Scan
            - dynamodb:GetItem
            - dynamodb:PutItem
            - dynamodb:UpdateItem
            - dynamodb:DeleteItem
          Resource:
            - Fn::GetAtt: [ TodoTable, Arn ]
  environment:
    TODO_TABLE: ${self:custom.tableName}


functions:
  hello:
    handler: handler.hello
    events:
      - httpApi:
          path: /
          method: get

# new
resources:
  Resources:
    TodoTable:
      Type: AWS::DynamoDB::Table
      Properties:
        AttributeDefinitions:
          - AttributeName: todoId
            AttributeType: S
        KeySchema:
          - AttributeName: todoId
            KeyType: HASH
        ProvisionedThroughput:
          ReadCapacityUnits: 1
          WriteCapacityUnits: 1
        TableName: ${self:custom.tableName}