As you want to get the details of eligibility criteria to give the exam of TRB so here is the information of the same for you:

For classes I to V:
Candidates must have passed Higher Secondary Course (10+2 Pattern) and Diploma in Teacher Education in a Recognized Teacher Training Institute / DIET

For classes VI to VIII:
Candidates must have passed a Bachelor’s Degree (B.A. /B.Sc. / B.Litt.) with Tamil, English, Mathematics, Physics, Chemistry, Botany, Zoology, History and Geography or a Degree with any one of the equivalent subjects from a Recognized University under 10+2+3 Pattern and a Degree in Teacher Education (B.Ed.) from a Recognized University. If u are appearing for the Final Year Examination of D.T.Ed / B.Ed. during the current Academic Year are also eligible to appear for the Tamil Nadu Teacher Eligibility Test (TNTET)

AGE:
Maximum 57 years