Installation of react native

Hi,
I am a beginner in react native, from visual studio code I launched the npm start command which worked well, I want to run the application on an emulator, I followed a tutorial which had a web page in localhost:19000 which I didn’t get, I need to see this page to start running on the emulator.
thank you for helping me.

what i got when i typed localhost:19000

{“name”:“FirstApp”,“slug”:“FirstApp”,“version”:“1.0.0”,“orientation”:“portrait”,“icon”:“./assets/icon.png”,“userInterfaceStyle”:“light”,“splash”:{“image”:“./assets/splash.png”,“resizeMode”:“contain”,“backgroundColor”:“#ffffff”,“imageUrl”:“http://127.0.0.1:19000/assets/./assets/splash.png"},“updates”:{“fallbackToCacheTimeout”:0},“assetBundlePatterns”:[“**/*”],“ios”:{“supportsTablet”:true},“android”:{“adaptiveIcon”:{“foregroundImage”:“./assets/adaptive-icon.png”,“backgroundColor”:“#FFFFFF”,“foregroundImageUrl”:“http://127.0.0.1:19000/assets/./assets/adaptive-icon.png”}},“web”:{“favicon”:“./assets/favicon.png”},“_internal”:{“isDebug”:false,“projectRoot”:“C:\\Users\\imane\\FirstApp”,“dynamicConfigPath”:null,“staticConfigPath”:“C:\\Users\\imane\\FirstApp\\app.json”,“packageJsonPath”:“C:\\Users\\imane\\FirstApp\\package.json”},“sdkVersion”:“46.0.0”,“platforms”:[“ios”,“android”],“iconUrl”:“http://127.0.0.1:19000/assets/./assets/icon.png”,“debuggerHost”:“127.0.0.1:19000”,“logUrl”:“http://127.0.0.1:19000/logs”,“developer”:{“tool”:“expo-cli”,“projectRoot”:“C:\\Users\\imane\\FirstApp”},“packagerOpts”:{“dev”:true},“mainModuleName”:“node_modules\\expo\\AppEntry”,“__flipperHack”:"React Native packager is running”,“hostUri”:“127.0.0.1:19000”,“bundleUrl”:“http://127.0.0.1:19000/node_modules\expo\AppEntry.bundle?platform=ios&dev=true&hot=false",“id”:"@anonymous/FirstApp-3d9589aa-1c21-436a-aae9-663bfebc30de”}

after running npx expo start, just press i for iOS or a for Android simulators.