After you have filed your NOD, your local VA office will prepare and mail to you a written explanation, known as the Statement of the Case (SOC), which describes the facts, laws, and regulations that were used in deciding your case. The intention of the SOC is provide you with a complete understanding of the VA's decision so that you may prepare an effective, substantive appeal with specific details as to errors of fact or law in your decision.
A VA Form 9 (PDF) (Appeal to the Board of Veterans Appeals) will be included in the SOC. If you wish to continue your appeal, you must complete and submit Form 9 within 60 days of the mailing of the SOC. Any new, additional evidence to support your claim will be submitted with the Form 9.
After review of your Form 9 and any additional evidence submitted, the VA will make a decision and render a Supplemental Statement of the Case (SSOC).
Like all other decisions, the SSOC will discuss the issues at hand and how the VA determines service connection and/or increases for them. If you are still dissatisfied with the VA's decision, you may file a Substantive Appeal.