Detailed syllabus explained here(Page 24)
What kind of posts you can expect :
VAO, Junior assistant, Bill collector ,Field surveyor, Draftsman, Typist, Steno-typist,…
NOTE : All the above information is from the notification issued by the government for the exam that was just completed. Do take a look for intricate details. The notification for the next year exam is the only authentic place to find steadfast details for the next exam. Kindly use the last year’s notification (given below) as reference.
Last Year's Notification for TNPSC Group 4:
Click here for the link