title: Custom Authentication flow with aws amplify cognito
body: <p>I want to create a custom signup Authentication Flow in aws amplify cognito service</p>
  <p><strong>What i Have</strong></p>
  <p>1.Enter Username</p>
  <p>2.Enter Password</p>
  <p>3.Verify user with Otp (Phone Number)/Confirmation Code (email)</p>
  <p><strong>What i want</strong></p>
  <p>1.Enter Username</p>
  <p>2.Enter Otp/Confirmation Code</p>
  <p>3.Enter Password</p>
  <p>How to achieve this SignUp flow using aws amplify cognito service,Else what is the best service or approach</p>