I have 2014 kia sorento. do you add antifreeze to the radiator?

Add it to the overflow bottle, you will see a "hot" and "cold" line on it, fill it to the appropriate line depending on whether the engine is hot or cold. Be sure to use the right type of antifreeze, open the overflow bottle and look at the color of the existing coolant, or consult the owner's manual.

what if i filled the radiator and not the overflow bottle- any danger in the operating vehicle?

Probably no danger in operating the vehicle other than it having a coolant leak if you filled the radiator.

Excess coolant will eventually overflow. No biggie.