Hi, Highskies, and welcome aboard! This can be a fun place, or at least a stimulating one....
But is this really what the author is saying? If we know that God created man last, on the 6th day, then the only logical conclusion can be that God planted the garden before he formed man.
Not the
only logical conclusion. One could also conclude, like several generations of "mainstream" Bible scholars have, that we have two old origins stories there in the first three chapters of Genesis, and that they were merged a long time ago by some rabbis that probably had what they felt were good reasons for doing so.