Composer+ is a template that runs on the TouchOSC app by Hexler. For this digital template to work on your tablet or smart phone, you will need to purchase the app separately.
However, one benefit of having a single account across most app stores is that if you buy TouchOSC for your iPad, you can also download it on your iPhone, making it ideal for both your main and phone Composer+ templates.
Visit the TouchOSC website
here