My friend has discovered many groundbreaking results on a specific topic in mathematics, which he finds really hard to configure them up at a single place, that is his first research paper, and also he has introduced a range of new tools with powerful skillsets, after struggling from many restrictions like those of symbols being already widely utilized, he managed to make them alright and unique as possible.
The important concerns which I wish to put here from his side is that where should he mention the Advisory & Caution note and Mathematics subject classification, moreover as above said it's really hard to configure them all up, means the Index of content is completely in chaos accordingly, so please provide some healthy suggestions on how to do that, and is it okay if he wants to say something specific on his exposition? Like Author's note in the end of paper and like before the References section? Please let me know where is the right place to do that.
Important note - I can't declare his educational qualification or name or any details except what mentioned above.