Layoff notice, what does the 60 days mean? (update)

I received a formal notice about a mass layoff at my workplace. I worked as an electrician's helper before this. Some colleagues are already leaving. Should I stay for the bonus?

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.

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