Should I upload the unsigned file or the signed file signed by the crt and key files Nokia sent to me?

As in qt creator help, smart installer part
Preparing Applications for Nokia Store or Symbian Signed
Building Smart Installer Packages for Nokia Publish
This gets an app_installer.sis.
It uses the crt and key files nokia send to me. And in the end, it says
Note: The above steps are sufficient if your application uses none of the following capability sets: AllFiles, DRM, TCB, CommDD, DiskAdmin, NetworkControl, MultimediaDD. If any of those capabilities if a must, first follow the instructions in Building Symbian Signed Smart Installer Packages to have the application Symbian Signed and then create the wrapper .sis package using the developer certificate provided by Nokia Store (as instructed above).
However, in the forum
Preparing Content for Nokia Signing using Qt Creator/Carbide.ui Symbian Theme Edition

Preparing Qt Content for Nokia Signing using Qt Creator
This gets an app_installer_unsigned.sis.
It suggests that I should upload an unsigned file.

So the question is, why they are different and which method should I use?
Thank you.