My supplement has two things in it. How do I record both?

Open the supplement and use What is in it. Add a row for each thing on the label, with its amount and unit. There is no limit. Kirkland Turmeric, for example, is turmeric 500 mg and black pepper extract 5 mg, and both belong in the record because the black pepper is there to change how the turmeric is absorbed. Rows stay in the order you enter them, which is the order the label prints them.