Via Online
visit Irctc.co.in
Login with your user name and password..
Give the station start and end station you want to travel.
Select date and type of ticket and whether its tatkal or gen...
Search...
more... for trains
12805 will appear if you searched for stops running in this train
Click the type of coach you want.. 2S or CC
Click the book button near the Availability status for the DOJ
then enter the details and then make payment..
Next page select the mode of payment and then click Book
Then next page Enter the details asked for and then click PAY
Ticket will be processed and appear in your screen...
Success. ticket has been booked.
Via PRS
Visit the nearest PRS and then take a reservation silp, fill the details, Stand in Queue and then when your turn comes, submit the slip, the amount , ticket will be booked