Hi, Deeksha!

Firstly, for your information TES Entry is only for boys. Regarding your question, well you get the notification on joinindianarmy.nic.in

Every year TES Entry changes it's cut off depending upon the overall result. It's usually between 80-90% with Physics, Chemistry and Maths as compulsory subjects and English as your language subject. If you're crossing the cut off then you're eligible for it and you don't have to appear for the written examination, you'll be directly going for the SSB that's Staff Selection Board. 

Note: You have to pass each subject with no compartments if you wish to apply for TES Entry.