Layoff notice, what does the 60 days mean? after 10 years as a mechanic

I received a formal notice about a mass layoff at my workplace. I do not usually post, so bear with me. I do not know if I should start looking now or wait for severance news. Has anyone been through this?

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

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.