Various technologies are now available that provide context-aware support for such informal online learning. In the case of formal and structured learning, the learning material is provided by a well-trusted instructor whereas in the case of a context-aware system that assists online learning there is a lack of such a trusted entity. Additionally, there is a lack of information about how the learning material is selected by the system. Providing users with the system-generated explanation of the basis of the selection of the learning material could help increase trust. An explanation has been found to be useful in building trust towards automated and AI systems but there is no evidence of the usefulness of explanation in building trust towards context-aware online learning assistants (CALA). In this project,  we investigate explanation for building towards CALA and investigate users' perception towards explanation and trust in the context of a context-aware system meant for educational purposes.