If you understand English it is perfectly clear what it means. The first part is just a reason why the right must not be infringed, but the right is specifically spelled out as a right of the PEOPLE not just a right of militia members, the states, or the federal government.
I understand English, Deutsch, American Sign Language, Pig Latin and YOUR interpretation of the second amendment. Nothing perfectly clear about the second amendment. Don't misunderstand me, I prefer your interpretation. Gun owners as a group need to be able to explain their position on firearm ownership, carry, open carry etc if we are going to make a difference. Quoting half of the second amendment every time an issue comes up is not the answer.