Hi,
Which development model are you using? ASPX or portal templates?
In general, the content of the web site is stored in the database. The home.aspx file your are writing about, is just an ASPX page template for home document - it has no content, just web parts and controls which are displaying content.
Could you please go through one of the tutorials to see how Kentico CMS works:
Documentation. I hope it will help.
Best Regards,
Juraj Ondrus