1 . Just point -settings.json files to your store.
{
"oauth": {
"appName" : "myamazingapp",
"api_key": "** Your Api Key **",
"client_secret": "** Your Client/Shared Secret **",
"redirect_url": "https://myamazingapp.com/auth_token",
"scope": "read_products, write_products" // here, goes yours scopes
}
}
2 . Create your app and add an admin link pointing to root of your app.
http://myamazingapp.com/
To install the app as a private app, access the root of your app with a shop url parameter having the domain name of your store, example:
http://myamazingapp.com/?shop=myamazingstore.myshopify.com