(By the Qur'an, full of wisdom) 36:2
means, Al-Muhkam (perfect) which falsehood cannot come to from before it or behind it.
(Truly, you) 36:3
means, O Muhammad,
لَمِنَ الْمُرْسَلِينَ عَلَى صِرَطٍ مُّسْتَقِيمٍ
(are one of the Messengers, on the straight path.) 36:3-4
means, following a straight methodology and religion, and an upright Law.
تَنزِيلَ الْعَزِيزِ الرَّحِيمِ
(Sent down by the Almighty, the Most Merciful.) 36:5
means, this path which you have brought is a revelation from the Lord of might Who is Most Merciful to His believing servants.
This is like the Ayah:
وَكَذَلِكَ أَوْحَيْنَآ إِلَيْكَ رُوحاً مِّنْ أَمْرِنَا مَا كُنتَ تَدْرِى مَا الْكِتَـبُ وَلاَ الإِيمَـنُ وَلَـكِن جَعَلْنَـهُ نُوراً نَّهْدِى بِهِ مَن نَّشَآءُ مِنْ عِبَادِنَا وَإِنَّكَ لَتَهْدِى إِلَى صِرَطٍ مُّسْتَقِيمٍ - صِرَطِ اللَّهِ الَّذِى لَهُ مَا فِى السَّمَـوَتِ وَمَا فِى الاٌّرْضِ أَلاَ إِلَى اللَّهِ تَصِيرُ الاٍّمُورُ
(And verily, you are indeed guiding (mankind) to the straight path. The path of Allah to Whom belongs all that is in the heavens and all that is on the earth. Verily, to Allah all matters return.) (42:52-53).
لِتُنذِرَ قَوْماً مَّآ أُنذِرَ ءَابَآؤُهُمْ فَهُمْ غَـفِلُونَ
(In order that you may warn a people whose forefathers were not warned, so they are heedless.) 36: 6
This refers to the Arabs, for no warner had come to them before him. The fact that they alone are mentioned does not mean that others are excluded, just as mentioning some individuals does not mean that all others are excluded.