Go to Home Depot and pick up some ant baits (assuming you don't have kids or pets around). Figure out where the bulk of them are coming from and to (they might have multiple trails) and leave the poisoned bait food in the path.

The stuff works, although it takes a couple of weeks to kill a nest, and sometimes new nests will pop up for a while. Eventually it will kill them all.

You definitely need to get some ant killer stuff such as Ant Out etc.

Also wash your floors/ surfaces with vinegar seems to help