Topping bread with poppy seeds or sesame seeds
You should sprinkle them onto the dough before baking. They shouldn't burn, but they will toast and release some tasty oils. You don't need to soak them either.

Using a wash depends on the wetness of your dough. If it's fairly wet, you'll probably be fine. If it's a drier, more stable dough, use a simple egg wash, which will help the seeds stick and give a nice glossy finish to the top of your loaf.