There are two types procedure to book luggage in Indian Railways:-
1. Parcel booking : I am not sure how they (Indian railways) came up with those terms but those are the two ways you can do this. Parcel booking can be done by going to your nearest station and filling a parcel form and you leave your goods there and you can expect it to reach your destination within five to seven days. To receive your goods you have to go to the destination railways station and present your receipt. You wont be traveling on the same train and it costs a bit extra as compared to luggage booking. Another important thing to note is parcel bookings can only be done during office hours on working days.
2. Luggage booking : This is what you want as you are planning to travel with your luggage on the same train. You should ideally reach the railway station at least three hours before the train departure (better to have time on your side). There are security checks and those guys are "slow" so keep that in mind.Recent Uri attack may have heightened security.