Dear Abhishek,

                        After doing FTIR analysis, you plot it in origin or any plotting software (Intensity (Y axis) vs wave number (x axis)), then, you can find different stretching and bending mode. The vibration band at different wave number are assigned to distinct group like CH3, OH, NH2. You can find it from FTIR table. Please go through following useful link

https://webspectra.chem.ucla.edu/irtable.html

http://www.chem.ucla.edu/~bacher/General/30BL/IR/ir.html

https://chem.libretexts.org/Reference/Reference_Tables/Spectroscopic_Parameters/Infrared_Spectroscopy_Absorption_Table

https://www.youtube.com/watch?v=XIWc9eT476c

Dear Abhishek,

Debashis Panda  is right but if you have not experience in FT-IR analysis ask to your Professor or someone to help you in the data interpretation.

Good luck

Dear Abhishek,

A good deal for your question is the book "Introduction to spectroscopy" by Pavia. There you will found more about the intensity peaks of each vibration mode. Also, you can see something about this by searching "assingments".

Best regards