How do you explain what kind of guideline a person has to follow?
Should I say "the guideline/rule is that" like the examples below?
"The guideline you need to follow on this assignment is that you should do a thorough research."
"The guideline I have been following is that I do a thorough research."
"The rule you need to follow is that you should do a thorough research."
Edit: Okay, maybe my question wasn't clear at all. What if I insist on explaining what kind of rule/guideline a student has to follow to a friend by using "the rule/guideline is that" construction? Is this construction not possible at all?
Should I say something like "you need to follow the guideline/rule, which is that you should do a thorough research"?