Before you connect the ant's test tube you should water the nest with mineral (bottled) water only (the watering hole is where the yellow Greek sponge is). Pour 1-3ml mineral water (depending on the size of your ant setup) once a week. Keep an eye on the humidity and reduce the water amount if needed. An article you must read before you go any further:
https://www.bestantsuk.com/post/how-to-set-up-your-new-ant-farm