Layoff notice, what does the 60 days mean? - any advice?

I received a formal notice about a mass layoff at my workplace. There are 8 people counting on me, so I am trying to be careful. Some colleagues are already leaving. Should I stay for the bonus?

I stayed for the retention bonus and looked for work on the side. It cushioned the gap.

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