Clean your sink as you would normally and dry it with a soft cloth.
Follow the instructions on the package for mixing the repair compound. The instructions generally include using a small wooden spatula or tongue depressor to mix the compound in a clean container to prevent any contaminants from entering the mix.
Apply a small amount to the chip, smoothing it with the wooden stick. Add a little at a time rather than applying large globs to the sink.
The compound may shrink as it dries, so overfill the area slightly, feathering it out at the edges. Scrape off any excess.
Allow the repair compound to dry for the time recommended by the manufacturer.
Sand the repair lightly with sandpaper until it is smooth and flush with the surrounding area.
Apply the touch-up glaze with a small paintbrush and allow it to dry. Avoid scrubbing the area for at least a week to allow the compound to fully cure.