Here are the steps to create a SharePoint Hosted App Project in Visual Studio.
Add your new SharePoint site (https://modernappz.sharepoint.com) and leave the app setting to ‘SharePoint-hosted’:
Sign in with your Office 365 account:
Your project is now created and you are now ready to implement your custom code:
Next we need to add a Client Web Part to our project which will serve as the ‘App Part’ that we will eventually add to our SharePoint page:
Replace the code in the newly created ‘ClientWebPartBlogs.aspx’ page in your ‘Pages’ folder.