Developments in the affordances of the Internet provide language learners with easy access to learning resources as well as interactions with native speakers. This emerging learning landscape thus creates favourable conditions to learners who want to engage in self-directed language learning. This in-depth single case study reports on the self-instruction language learning practices over three months by a Filipino female learner of Korean. The Korean learner had the goal to work in a Korean factory and subsequently started to self-instruct Korean language learning to pass the high-stakes exam imposed on low-skilled migrant job seekers by the South Korean government. Drawing on the concepts of 'agency', 'affordance', and 'context', this study analysed the use of YouTube by a self-directed learner of Korean to design and create personal learning contexts. The study found that the participant exerted agency to construct highly personalised learning contexts across multiple learning stages. The participant located video clips and information relevant to her learning goals by strategically acting on the technological and social affordances embedded in the online applications. Using the multiple affordances provided by YouTube, she created highly personalised learning contexts to cater to her learning needs. The findings also suggest that the participant's agency was mediated by personal, socio-cultural and technological factors. Thus, this study extends our understanding of the role of learner agency in creating self-instruction learning contexts in the digital age.