How about I just make it easy on you. Read the following:
E-1 = Seaman/Fireman/Airman/Hospitalman/etc RECRUIT (SR/FR/AR/etc)
E-2 = Seaman/Fireman/Airman/etc APPRENTICE (SA/FA/AA/etc)
E-3 = Seaman/Fireman/Airman/etc SN/FN/AN/etc
If a person has a "job description" or "rating" then it would preceed the above "rate" such as MMFA, ETSN, EMFR, etc
If a person does not have a "rating" then they are simply a SA, FN, FR, etc.
E-4 = Petty Officer Third Class which is designated by a 3 after their "job description" or "rating" such as MM3, EM3, ET3, etc
E-5 = Petty Officer Second Class(same as above for rating only using a 2 instead 3)
E-6 = Petty Officer First Class(Same as above for rating)
E-7 = Chief Petty Officer which is designated by a C after the rating such as MMC, EMC, ETC, etc
E-8 = Senior Chief Petty Officer is designated by a CS after the rating such as MMCS, EMCS, ETCS, etc
E-9 = Master Chief Petty Officer is designated by CM after the rating such as MMCM, EMCM, ETCM, etc
Also as stated above, you have Warfare designators after the ratings(yes you can have more than one).