Students can't do it all. Pick what to focus on. For the beginning researcher, research can be a complicated process with many steps to master effectively. Your assignment might want to prioritize some of those over others.
Students experience a greater cognitive load when researching because they lack domain knowledge. You can help students focus their energies by ensuring your assignment matches your priorities.
For example, to prioritize synthesizing arguments, design an assignment around reading and writing with sources, and limit the need for finding sources. To prioritize identifying the scope of research on a topic, require searching for sources.
Prompts should address both the steps along the way (picking a topic, collecting data, synthesizing sources) and the completed assignment. When instructions focus only on the final product, students will view them as a checklist to complete.
For example, requiring a certain number of sources for a paper directs students' attention to the end product. Students will pick the first sources they find, rather than understanding the process of finding many possible sources, then selecting the best ones.
Break down and explicitly teach the different aptitudes students need to be successful. Research can overwhelm students, especially those new to the process or discipline.
Make your assignment relevant to real life experiences and skills. Students learn best and successfully transfer what they're learning when they connect with the assignment, feel the excitement of discovery, or solve challenges. Through disciplinary and experiential learning, students develop different perspectives from which to view the world.