Hi.
You need an input file where the atomic polarizabilities for the relevant atom types are supplied, together with the mass of the drude particles and the force constant for the core-dude bond. Then it just works as described in the documentation https://lammps.sandia.gov/doc/Howto_drude2.html
I recommend that you start with a simple example, e.g. ethanol following the paper by Noskov, Lamoureux and Roux, J Phys Chem B, 109, 6705 (2005).
Agilio