Bibimbap Recipe from Maangchi's Korean Cookbook

I got Maangchi’s cookbook for Christmas and I’m finally ready to try it out, but the bibimbap recipe has me perplexed. It calls for flank steak, cut into matchsticks, plus other ingredients for seasoning. The instructions say to mix those ingredients together and put them in the fridge until ready to use, and the next time the flank steak is mentioned it is to arrange it on top of the rice.

I’ve only eaten bibimbap once, but I’m pretty sure the meat was cooked. I can see three possibilities that would fit with what’s in the cookbook:

1. Cook the steak, then cut into matchsticks, then add seasoning.

2. Cut the steak, cook it, then add seasoning.

3. Cut the steak, add seasoning as marinade, cook right before serving.

My instinct is to go with the third option, but Maangchi is pretty clear about when and how to cook the other ingredients in the recipe so I’m really not sure. Her bibimbap recipe on the website uses ground beef, so it isn’t the same process. Does anyone have any advice?

Thanks!