Can’t add GST Tax on top of Stripe Checkout Price

I’m struggling to add GST (Tax) to my stripe checkout. totalBill is the final amount, but I want to add 10% GST (Australian Tax). What do I need to do to have it displayed and calculated in my Stripe Checkout?

Thanks in advance, pulling my hair out over this one!

const product = await stripe.products.create({
      name: `Service for ${name} + GST`,
      tax_code: "txcd_99999999",
    });
    const price = await stripe.prices.create({
      currency: "aud",
      unit_amount: totalBill * 100,
      product: product.id,
    });
    if (price) {
      const customer = await stripe.customers.create({
        email: email,
        name: name,
        address: {
          line1: addressLine1,
          city: addressCity,
          state: addressState,
          postal_code: addressPostalCode,
          country: addressCountry,
        },
      });
      if (customer) {
        session = await stripe.checkout.sessions.create({
          payment_method_types: ["card"],
          line_items: [
            {
              price: price.id,
              quantity: 1,
            },
          ],
          customer: customer.id,
          customer_update: {
            address: "auto",
          },
          mode: "payment",
          success_url: `URL`,
          cancel_url: "URL",
        });
        const customerid = customer.id;
        customerStripeURL = `https://dashboard.stripe.com/customers/${customerid}`;
      }

You should create a tax rate for GST first, and specify the resulting tax rate ID in the line_times.tax_rates during checkout session creation.