What is the job of an LD Clerk?? How to become one?

I am a differently-abled person on wheelchair. I finished my 12th. I live in Kerala and am planning to write PSC exam for LD clerk post. Could u pls tell me about this job. What will the work be? What is the basic salary? Being on wheelchair, will i be able to get the job..? Any help will be greatly appreciated. Thanks!