Severance and unemployment, do they overlap? - any advice?

My employer is paying severance in instalments and I am not sure whether to file now. This is my first time dealing with any of this. I have a mortgage and need to plan. Did you file straight away?

Rules differ by state. I called the claims line and asked directly, then wrote down the answer and the date.

I filed on day one anyway and reported the severance honestly. The agency decided what to do about the timing.