Assume it has not been properly seasoned before you bought it. Put it in the oven at its maximum heat and burn everything off of it. When cooled scrub it well with soap and water and comet. You now have a clean skillet that needs to be seasoned properly.
Place again in the oven at about 275 degrees with oil in the skillet for about an hour. I like to use lard but other oils will do. Canola is a high temperature oil and does nicely but I like lard better. Lard is a lower temperature oil but seems to season better in my estimation. If it starts smoking your oven is to hot take it out immediately.
If properly seasoned you will have a black sheen on the bottom of the skillet. Never wash it again with dish soap.
To clean use a mildly abrasive brush and water.
If by chance you use the skillet at to high a temperature and ruin the seasoning, it is ruined period. Start the whole process over again in the high temperature oven. It is kinda irritating but when you ruin a teflon skillet it is over, throw it in the garbage can. That wonderful cast iron skillet can be returned to new for many many years.
Cast iron takes a bit of love and care but it cooks the best. My beloved wife is refused access to my cast iron. If she burns out a teflon skillet what the hell, stay away from my cast iron.
Just curious about some of that French Cast Iron with an enamel coating? It looks nice. Any masters of the kitchen have experience with it. I have considered buying some but just do not know if it is any good?
Le Creuset is the best (even if it is Frog Ware). Very pricey. I paid over $300 for a 6qt oval Dutch oven. Just used it yesterday to make corned beef. Also use for deep fat frying. It holds the heat forever - don’t be in a rush.