If you don't get what your research supervisor is instructing you to do, ask for clarification until it makes sense and you fully understand the plan. You can't fake your way through your project.
Sometimes it’s unnerving to ask for clarification when you don’t immediately grasp a concept or understand a statement your supervisor or mentor says. He might seem rushed or distracted. You worry that she will think less of you for needing a more detailed explanation.
The reality is that most supervisors and mentors would rather you ask them to clarify when you don't understand something even if you need to ask several times. Need the right words? Use the phrase, “I’m just not getting it. Can you explain in a different way?”
It's possible that you'll need to do some reading to fully understand a concept or a research strategy, but if your mentor thinks it’s important enough to bring it up, it's important enough for you to understand it.