Just some things out of my head we can do to get started:
Email signed up members to join the forum
Start a few topics, get people to comment.
Cancelled tasks. Defer official registration till we have 10,000 members?.
Prepare a constitution and vote on it
Propose and select office bearers
Start collecting 100 affidavits
Start preparing for application. This is massively complex, requires several affidavits and NOC from Municipality and what not. This might take a few months to get started. Most likely we might need the help of an expert to navigate through this. There are ~3000 political parties in India, I am hoping this is a solved problem.