Step 1: Fill out Green Card application form
Step 2: Proof read the form
Step 3: Sign the form.
Step 4: Go to Post office.
Step 5: Buy the stamp and mail the form. (Note: Don't forget to pay for stamp)
Step 6: Wait for card in your mail box
Step 7: Proof read the name on your new green card.
Step 8: Make sure that the card has only your name not your US citizen wife's name.
PS: Your US citizen wife does not have to apply for Green card.
That's the process I followed when I did mine.