A skincare routine laid out in order, one step at a time. Pick the steps you already use, see where a serum fits, and keep the list short enough to follow.
Short and light, before the day starts.
The same order, slower.
Add a new product on its own, so you know which step you are looking at.
Check the ingredient list before you buy, and test on a small patch first.
A routine is a habit, not a treatment. For a skin condition, ask a dermatologist.