Complex sentence: Wani left home to become a militant at age of 15 and used social media Kashmiri youth angered by the "never-ending militarisation" of the Valley were drawn to him and his constant presence on the social media made him a household name.
Split into simpler sentences: Wani left home to become a militant at age of 15 and used social media to reach the Kashmiri youth who were angered by the "never-ending militarisation" of the Valley. They were drawn to him and his constant presence on the social media made him a household name.