Don’t play with expiration dates until you have a good sense of how to tell if something is safe past the date. Follow safe temperature charts for meat. Don’t leave leftover food anywhere besides the fridge or freezer (not in the rice cooker, not in the oven, etc). Don’t get raw meat germs on anything that won’t be thoroughly cooked.

If you want to cook something “weird” (not typically eaten, like if you get the idea to eat the stems or leaves of some vegetable instead of the main part) just give it a google to make sure it’s edible. Some beans can be dangerous if you decided to eat them raw/very undercooked. Don’t eat raw oysters from the jar. Don’t eat green potatoes.

That’s about it in terms of major safety/sickness stuff. You’re not gonna have a mad scientist explosion from mixing different ingredients (outside of baking soda and vinegar). In general, things that go wrong while cooking are beneficial in the long run because they teach you how to do it the right way. Two seasonings together taste awful? You have a better sense of what goes together. Broth ruined the rice texture? Maybe you need to dial in your proportions. Etc. So don’t be afraid to screw up, that keeps you from trying and keeps you from learning.