A new cast-iron skillet will require you to first use a steel wool pad on it, with water, to get the inside surface as smooth as possible. Then, take the pan and rub vegetable oil all over it and stick it, upside down in the oven. Set the temperature for the highest setting and leave it in there for an hour. Let it cool and take it out.
Your pan is not "seasoned", but it will be basically a non-stick pan. So, from then on, cook with the cooking oil of your choice, and when you're done cooking, leave the pan hot and clean with a Teflon pad an water, no soap. Then, lightly oil the inside of the pan again before putting it away.
I have a cast iron skillet that is 70-years-old. In my family, that's a "new" pan. So, take good care of your pan, it can last you several lifetimes.