If you are asking abt Inter Regn form, then REGN box is for office purpose..,
1. If you register with in 5th DEc, you can appear for june 13 exams, if you complete comp trng and GDBC,
2.. After passing Inter there must be gap of 9 months, means you can appear Final in june'14.
3. GD/BC conducted at chapter office, it will be one or two days, and comp trng..its fee abt 6000/-, and chapter will recommend at which institute..you have to attend, and it will be of 100 hrs,
4.ID card.., I think you get it along with regn form, or you can download on RC's website and send it along with regn form, You have to carry this ID card to exams venue..,
5. CC..its test papers for postal coaching students, but now they are dropping it..but still not yet announced officially...but its no more reqd while applying exams...
All the best