How do I download iPhone SE

Open the App Store app. It's a blue app with a white A in a white circle.

The iTunes Store app for iOS is not the same application

Tap Search. It's a magnifying glass icon at the bottom (iPhone) or top (iPad) of the screen.

Type itunes store in the Search field. It's at the top of the screen.

Tap iTunes Store when it appears in the search results.

Tap GET. It's to the right of the iTunes Store icon.

Tap INSTALL. It appears in the same location as the GET button. The iTunes Store app will be downloaded to one of your iPhone's Home screens.

[Edited by Moderator]

iTunes - the programme is not used on the iPad or the iPhone. Instead, to play the music, use the Music app that is already installed on the devices.