The executables should be under Program Files, who's precise location may vary from installation to installation. This means that the setup should run elevated. If InnoSetup makes .msi files, they will request elevation. If it makes a file called setup.exe, it will also request elevation. If for some reason the exe has a different name, like GetStarted.exe, then you should hand create an external manifest (GetStarted.exe.manifest) and put in requireAdministrator for the requestedExecutionLevel which will ensure your installer requests elevation.
Regardless of how it requests elevation, if the user doing the install is an admin (eg you) they will just have to click consent. If they are not an admin they will need to get an admin to consent for them. After that the installer will be able to write to Program Files.
If it's important to you that non admins be able to install the app then have the executables go under the users profile - but that would not be my first choice. The protection given to Program Files means that users are less likely to find themselves with messed up copies of your application if you install it to the protected area.