Choose a shallow dish, tray, or saucer
Fill it with clean sand, soil, or a mix of both
Add enough water to make it damp, not flooded
Place it in a sunny, sheltered outdoor spot
Add a few flat stones or pebbles for landing
Mix in a little compost or mineral-rich soil if desired
Keep the material moist by adding water regularly
Refresh the sand or soil when it becomes dirty
Avoid pesticides and chemicals nearby
Place it near flowers or butterfly-friendly plants