Here is a tutorial from vaspwiki:

https://cms.mpi.univie.ac.at/wiki/index.php/Dielectric_properties_of_SiC

And the links to previous questions in research gate about the same topic:

https://www.researchgate.net/post/How_to_calculate_the_dielectric_function_using_vasp

https://www.researchgate.net/post/How_can_I_see_Dielectric_constant_in_OUTCAR_of_VASP

Dear Sinhue,

Thank you for your help. But one thing is that , how can I get dielectric constant for infinite frequency ie, I want to calculate epsilon_infinity. How can I get this ?

now the question is not "How do I do that" bunt "Why would you do that"? the only scenario I can imagine for that case is X or G rays. It will be helpful if you have a look at the theory first because epsilon(infinity) is w=0 case = static. btw, the tag is omegamax.

At very high frequency, the dielectric constant of a material boils down to just its electronic contribution. You can get that from a standard DFPT calculation using VASP.