Identify your use: topping for bread/muffins vs. mixed into batter/dough.
Choose a substitute that matches the job: speckling (black sesame/chia/flax) or crunch (oats).
Use the listed ratio; if your substitute is stronger (sesame) or can taste bitter (chia), start at the lower end of the ratio.
For more even distribution, lightly crush sesame seeds or pre-mix the ground substitute with a spoonful of flour from your recipe.
Bake as usual, then taste once cooled—adjust bitterness next time with a smaller amount or by blending with a milder flour.