You will find a lot of information about it in some other threads and in the google also. But one information which turned out to be very crucial for me was that I did not have working time mentioned in my offer letter. So, I would suggest you to take original of your contract/ offer letter and make sure that it mentions that you are supposed to work 8 hours a day, 5 days a week. You need this information to get your registration at the SHRAM BIVAG done. You won't have any problem for your H1b. Good luck!