Possible meanings are 1) God was referring to one human, the man, or 2) God was referring to humans in general, so this would mean the man and his wife. Even if God was speaking about one person, what he said applied to both of them.
like one of us
"like us." The pronoun "us" is plural. See how you translated "Let us make" in Genesis 1:26.
knowing good and evil
Here "good and evil" is a figure of speech that refers to both extremes and everything in between. See how you translated "knowledge of good and evil" in Genesis 2:9. AT: "knowing everything, including both good and evil" (See: rc://en/ta/man/translate/figs-merism)
he must not be allowed
This can be stated in active form. AT: "I will not allow him" (See: rc://en/ta/man/translate/figs-activepassive)
tree of life
"the tree that gives people life." See how you translated this in Genesis 2:9.
the ground from which he had been taken
"dirt because he had been taken from dirt." This does not refer to the particular place on the land that the God took man from.
So God drove the man out of the garden
"God forced the man to leave the garden." This refers to the event in Genesis 3:23, where it says "Yahweh God sent him out of the garden of Eden." God did not send the man out a second time.
This means to what is needed so that plants grow well. See how you translated this in Genesis 2:5.
in order to guard the way to the tree of life
"in order to stop people from going to the tree of life"
Possible meanings are 1) a sword that had flames coming from it or 2) a fire that was shaped like a sword. Languages that do not have swords could use another weapon such as a spear or arrow.