The devil and his angels were cast to this earth.
As a result, he focused his deceptions on human beings.
God created Adam and Eve as perfect beings. In fact they were a perfect couple, in a perfect environment with a perfect God.
Like Lucifer, Adam and Eve were given a free choice to decide between good and evil.
God gave to Adam and Eve the most beautiful garden, plenty of friendly animals and a personal friendship with each other and God Himself.
However, He asked them not to touch or eat from one of the trees in the garden, the tree of the knowledge of good and evil.
This was a test of worship and obedience.
The devil used the serpent as a medium to deceive Eve into disobeying God.
Eve chose to trust her feelings and the word of the serpent instead of obeying the Word of God.