There are two methods:
(1) with Apple Developer Program License (99USD/year)
(2) just with Apple ID (free) + XCode 7 (currently beta)

The method (2) is chosen and done as follow:

cf. "Provisioning and Development" page in iOS Developer Library

cf. "App Distribution Quick Start" page in iOS Developer Library

- Introduction
- Setup
-- need apple ID and then
-- apple developer membership: enroll as an individual <= skip this step for development and test only (not distribution)
- Adding Your Account to Xcode
- Creating Your Team Provisioning Profile <= it seems that this can also be done in Preference > Account > View Details
-- code signing error => Clean and Build again
- Launching Your App on Devices <= select device in not Scheme pop-up menu but Product > Destination pop-up menu