Yes, the link showed only what the problem was and not how to fix it.
I found the solution myself which I want Microsoft to write as ....

Steps to get rid of apps.manifest
1) Open the project and click 'View', 'Solution Explorer'
2) By default all the files are NOT listed, so make sure to click 'Show All Files'
(Here is IT professional's common problem in assuming everyone knows this.)
3) Select 'My Project'
4) Select apps.manifest (without 'Show All Files' this link is NOT shown.)
5) Delete the link.

I want this type of step by step instruction!