I started a box of mulch items - junk mail and cereal boxes , torn into bits.
it’s fun ;)
I don’t tear them. I leave them flat so I can overlap them for a ‘barrier’. I put the leaves/hay/etc on top of that to keep the newspapers and boxes from blowing all over the yard :)
https://www.youtube.com/watch?v=H3Mc75MxR3M
I’d personally overlap the cardboard pieces a few more inches each way than these people did. But the idea is the same.