Step by step instructions.
Start here: https://snack.expo.io
You can see a complete app here: https://snack.expo.io/@quinlanj/poke-workshops2
Welcome to Expo!
Open the App.js file to start writing some code. You can preview the changes directly on your phone or tablet by clicking the Run button or use the simulator by clicking Tap to Play. When you're done, click Save and share the link!
When you're ready to see everything that Expo provides (or if you want to use your own editor) you can Export your project and use it with expo-cli.
Projects created in Snack are publicly available, so you can easily share the link to this project via link, or embed it on a web page with the Embed button.
If you're having problems, you can tweet to us @expo or ask in our forums.
Snack is Open Source. You can find the code on the GitHub repo.