Some of the most difficult parts of the Confessions are the final chapters as he reflects on Genesis 1:1. But you do see a great model of interpreting Scripture:
I wish to have none with any who think that Moses wrote what was not true. But I pray that in you, O Lord, I may dwell in harmony and joy with those who feed upon your truth in the fullness of charity. May they and I together approach the words of your Book, and in them may we seek your meaning as we were meant to understand it by your servant [Moses], through whose pen you delivered those words to us. (Book XII, s23)
Firstly, he equates Moses words with God’s words. God’s truthful meaning is tied to objective authorial intent. This is a good doctrine of dual authorship and infallibility, if not inerrancy.
Secondly, he reads the Bible prayerfully using all his cognitive gifts, looking to spiritually feed upon the Bible.
Thirdly, he reads the Bible with others, not controlled by some ecclesiastical interpretative authority, but seeking harmony with others and charity.
In this paragraph alone you see Augustine modelling in the fourth century what was taught to me as basic Protestant evangelical hermeneutics, such as in J. I. Packer’s, God Has Spoken.
UPDATE 3rd Nov:
One comment I didn’t engage with was Augustine’s allegorical or figurative exposition of Genesis 1 throughout the last sections of the Confessions. I don’t think this is a good way to read Scripture, in most cases. Augustine himself comments:
But let my confession, too, find favour in your sight, O Lord, for I confess that I do not believe that you used these words except for a special purpose, and I shall not hesitate to give the explanation which occurs to me as I read them. My explanation is consistent with the truth and I see nothing to prevent me from interpreting the words of your Scriptures in this figurative sense. (Book XIII, s24)
Augustine shows he is more controlled than your typical allegorical reading because a) he seems to be submitting them in the context of authorial intent as outlined above. i.e.: Moses had such figures in mind, b) he is still relying on cognitive reflection rather than supernatural imposition on the text, c) he cross-references and cross-checks himself with lots of other biblical quotes more literally derived, and d) he seems cautious, even unsure, about what he is doing.
So I think although he does cross a line into allegory, he is at the more saner end of the allegorical spectrum, and I think the first quotes above about authorial intent are still his overarching hermeneutical foundation.