In mixed methods research, sequential exploratory designs begin with a qualitative study where the goal is to generate input for a subsequent quantitative study (qual --> QUAN). A typical example would be to use focus groups as a method for developing the content of a set of survey items.
Sequential exploratory research is an investigation approach involving two distinct phases: qualitative and quantitative. In the qualitative phase, researchers collect data through interviews or observations to deeply understand the research problem. They then analyze the qualitative data to identify common themes or patterns. In the quantitative phase, researchers utilize a larger sample size to collect data through surveys or experiments. Afterward, they apply statistical analysis techniques to the quantitative data to identify relationships or trends. Finally, they integrate the findings from both phases to comprehensively grasp the research problem. Here is a helpful textbook.
Creswell, J. W. (2022). A concise introduction to mixed methods research (2nd ed.). SAGE. https://us.sagepub.com/hi/nam/a-concise-introduction-to-mixed-methods-research/book266037