Provide advice on how to accomplish the following goal. Give ONLY the advice, no other words or explanation.
For example:

Answer: <advice, as short as possible; a single sentence!>.

Goal: To slice cookie bars in a pan,
using a chef's knife, press down into the cookie bars until you feel it slice through to the pan, making horizontal and vertical lines of equal distance across the pan.
Use a sharp knife to cut cookie bars in a pan.