Easy enough, just buy the planks where you can find them. I’m sure you can order them from specialty shops, find these or cedar planks at home depot or equivalent, Williams-Sonoma, Whole Foods, Fresh Market, etc. Soak them for as long as you can stand it. The longer the better, and 24 hours isn’t too long. You can see that mine caught a bit on fire, but it worked out. Simple seasoning with salt, pepper, olive oil, and I added oregano to give it a bit of a Greek/Mediterranean flair. Cook until flaky, no turning, skin side down.
Finish with lemon juice and serve on the plank. Simple, good eats.