My research investigates the intersection of self-directed online resource use, individual differences, and computer-based second language (L2) writing. As the integration of multiple web-based resources becomes ubiquitous in real-world writing practices, there is a pressing need for empirical research and theoretical models that capture how learners navigate these tools. To explore these complex dynamics, I employ a robust mixed-methods approach. By combining advanced process-tracing technologies (such as keystroke logging, screen recording, and eye tracking) with in-depth qualitative methods (such as stimulated recall interviews and surveys), my work aims to provide a comprehensive understanding of the cognitive and behavioral mechanisms that underpin computer-assisted L2 writing.