For how to load the signed app (.ipa) to the iOS device via iTunes, please refer to the "Installing Your App on Test Devices" section on this Apple Developer page.
The Adobe Digital Publishing Solution platform will only store the unsigned version of the app. The signed app generated by the Adobe Publishing App Signing Tool will be local to your computer, within the same directory that the unsigned app was downloaded to. i.e. if the unsigned app was downloaded to the default "Download" folder, then the signed app (with suffix "-signed") will also be in the "Download" folder.