Access 2013 Custom Web Apps

I was trying to build a custom web app in Access 2013. The configuration of App model "On Premise" is not completely documented at a single location. After refering to blogs and posts for configuration for "On-Premise" I reached to a stage where the App was hsoted on the Web Application and the tables and custom database was created on SQL Server instance. But Secure Store connection was giving an issue. I decided to go with OFfice 365 version of SharePoint and the app worked on the cloud. The learning of which is as follows

1. You cannot change Primary Keys in the table you create. By default an ID with AutoNumber is the primary key.
2. No easy option to write code routines. The GUI is okay for smaller snippets not for long routines.
3. No user freindly error messages - all you see it "Something went wrong" - and when you click on Technical Details you only see a correlation ID.
4. No easy way of debugging.
5. Very little help and learning material on Microsoft site.

Hopefully with time and upgrades - the building of apps becomes much more enjoyable experience.