Crocheters/Knitters: How would I block this piece?

I’m working on this shawl, and it needs to be done for Sunday. I’ll have the crocheting done by then, but I’ve never blocked before.

I’ve googled it, but there are so many different opinions on the best way to block. The yarn I’m using is 96% acrylic, 4% metallic polyester.

Can I block on a piece of cardboard? Where, ideally, should I place the pins here? And what’s the best blocking method for something like this?