I'm new to Shopify app developing I create new app npm init @shopify/app@latest install it to shopify store, and now try send token to backend i try this code : import React, { useEffect, useState } from 'react'; import { getSessionToken } from '@shopify/app-bridge-utils'; import createApp from '@shopify/app-bridge'; import { Box, Card, Layout, Page, Text, BlockStack } from '@shopify/polaris'; export default function AdditionalPage() { const [iframeSrc, setIframeSrc] = useState(''); useEffect(() => { // Parse the query parameters const params = new URLSearchParams(window.location.search); const apiKey = params.get('apiKey'); const shopOrigin = params.get('shop'); if (!apiKey || !shopOrigin) { console.error('Shopify app configuration is missing!'); return; } // Initialize the Shopify app bridge const app = createApp({ apiKey: apiKey, shopOrigin: shopOrigin, forceRedirect: true, }); // Get the session token getSessionToken(app).then((token) => { const urlWithToken = `https://myurl?session_token=${encodeURIComponent(token)}`; setIframeSrc(urlWithToken); }).catch(error => { console.error('Failed to get session token:', error); }); }, []); return ( <Page> <ui-title-bar title="Panel" /> <Layout> <Layout.Section> <Card> <BlockStack gap="300"> <Text as="p" variant="bodyMd"> This is an example of how to include an iframe within your Shopify app. </Text> <iframe src={iframeSrc} style={{ width: '100%', height: '500px', border: 'none' }} title="Dashboard" loading="lazy" /> </BlockStack> </Card> </Layout.Section> </Layout> </Page> ); } function Code({ children }) { return ( <Box as="span" padding="025" paddingInlineStart="100" paddingInlineEnd="100" background="bg-surface-active" borderWidth="025" borderColor="border" borderRadius="100" > <code>{children}</code> </Box> ); } but there is no token, how i should get it ? (or autorise backend - need token and shop domain)