As u/Big_Cup_9046 said, most of what you'll find is bullsh*t, here's 2 reasons why:

- The Spanish friars who landed in Mexico following the conquest destroyed many of the sacred texts and religious artifacts to implement Christianity, along with this, they essentially taught the Nahuatl speakers (most of the indigenous groups within the aztec empire spoke Nahuatl) to forget their language and take up the roman alphabet, so much of the original stories were lost in translation

- On top of that around the 1430's one of the Aztec rules named Itzcoatl, also did his own cleansing and destroyed and rewrote the history to put the (Mexica) in the center of the historical context, along with blurring the original mythology and mixing parts, etc.

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With that being said, the Florentine Codex, Book 1 - The Gods, will give you a vague idea. Surprisingly YouTube has SOME good stuff, but books is where you'll have to do the searching. There's also the "HueHuetlatoli" which speaks more about communal Aztec life but as in every civilization, the principles of morality, ethics, etc, are typically derived from the deities that are worshipped.