Those insects are attracted to easily accessible food. Maybe they moved from neighboring houses or were brought with stuff, furniture, and products. It is much easier to prevent the appearance of ants than fighting them. But if those little guys already visited your apartment you should read these hacks about how to get rid of them. Hope it will come in handy for you.

it is advised to sprinkle the places where the ants invade the house with flour or talcum powder, use scotch tape, salt and ground pepper and other folk remedies for fighting.