Severance and unemployment, do they overlap?

My employer is paying severance in instalments and I am not sure whether to file now. I do not usually post, so bear with me. The agreement mentions a release and a payment schedule. Who should I ask before signing?

Keep everything in writing and save the confirmation numbers. It saved me later.

Before signing, I asked a friend who is a lawyer to look at the agreement. It was a short conversation and worth it.