Tutorial on how to use this API for beginners

Hi, I'm fairly new to AWS cloud services and I'm using Stripe for the first time to make a Checkout with Subscription. It would be lovely if you could share a tutorial for beginners, or a YouTube link like you mentioned in ReadMe.

I am planning to use this api-lambda-stripe-charge for backend, and ngx-stripe-checkout for the front-end (Angular/Ionic).

I completed the first 3 setup steps. And for 4 and 5(note that the integration part in this link https://stripe.com/docs/checkout#integration is no longer there) I believe this ngx-stripe-checkout has a different way of calling the checkout, but I'm guessing the functionality should be the same:

// For Recurring Payments
// Invoke this function on button click
   openSubscriptionCheckout() {
    var checkoutOptions: RecurringCheckoutOptions = {
      items: [{
        plan: 'your plan id',
        quantity: 'quantity'
      }],
      successUrl: 'https://example.com/payment/success',
      cancelUrl: 'https://example.com/payment/failure'
    }
    this.stripe.openRecurringCheckout(checkoutOptions);
  }

Now I cannot test the functionality, because our company account is not yet activated. I'm guessing Stripe doesn't let us call Checkout with TEST products, because I get the following error:

IntegrationError: No such plan: '<my TEST plan id here>'

But I'm trying to set the code-base until the account is ready, as we are close on our deadline. I am kind of confused about how the lambda function will be triggered, after I make a checkout call to Stripe. Shouldn't there be a connection between Stripe and our backend to handle charges/refunds etc.? Should I call the lambda API from frontend in success/cancel pages? I would appreciate it one can enlighten me.