Layoff notice, what does the 60 days mean?, machine operator here

I received a formal notice about a mass layoff at my workplace. I am in Wichita, in case local advice matters. I do not know if I should start looking now or wait for severance news. Should I stay for the bonus?

Write down key dates and keep copies of the notice. Mine helped when a question came up later.

Start your search early. I wish I had begun the day of the notice.