Severance offer, what should I ask for?

The company sent a severance agreement with a release of claims, and I am unsure what to do. This is my first time dealing with any of this. I do not want to leave money on the table. Did anyone negotiate and succeed?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

I asked for two more weeks and a neutral reference. They agreed to the reference and added a week.