The conceptual framework of your study is the system of concepts, assumptions, expectations, beliefs, and theories that supports and informs your research. It is a formulation of what you think is going on with what you are studying—a tentative theory of what is happening and why.
Theory provides a model or map of why the world is the way it is (Strauss & Corbin, 1990) The function of theory in your design is to inform the rest of the design. The “research problem” is a part of your conceptual framework, and formulating the research problem is often seen as a key task in designing your study. Ravitch & Riggan (2016) define a conceptual framework as an argument about why the topic one wishes to study matters, and why the means proposed to study it are appropriate and rigorous. By argument, they mean that a conceptual framework is a series of sequenced, logical propositions the purpose of which is to ground the study and convince readers of the study’s importance and rigor. Arguments for why a study “matters” vary greatly in scale, depending on the audience.
In some scholarly work, the study may only matter to a small, esoteric community, but that does not change the fact that its conceptual framework should argue for its relevance within that community. By appropriate and rigorous, they mean that a conceptual framework should argue convincingly that: (a) the research questions are an outgrowth of the argument for relevance; (b) the research design maps onto the study goals, questions, and context(s); (c) the data to be collected provide the researcher with the raw material needed to explore the research questions; and (d) the analytic approach allows the researcher(s) to effectively address (if not always answer) those questions. In order to start building the conceptual framework for your research project we truly recommend the following book:
Ravitch, S. M., & Riggan, M. (2016). Reason & rigor : how conceptual frameworks guide research. Thousand Oaks : Sage Publications. The following figure represents and briefly explains the main components a conceptual framework should have.