To write a good explanation on the nameplate, you should not classify pieces at the group organization phase. Suppose you think that "this is a cause of the problem, this is also a cause of the problem." What nameplate is attached to this group? Since there is only a relation those are all the cause of the problem, you make a nameplate says "cause of the problem." However, with this nameplate, you do not understand the contents of the group at all.

The reason why you can not make a good explanation is that there was not any relation other than "these are all cause of the problem" in those pieces. To make those pieces into a group is not good.

You can not get the skill of group organization by reading books. You need to try it. After you made a group, you can verify it is a good group or not, by making a nameplate. You can realize the difference between a group that can summarize the contents well and a group that is not so. By doing this exercise, you gradually acquire the skill to organize good groups.