Yo can expect the bedding that the room description states. In this case, you have booked a room that has 1 king bed

If you need more than this, then as suggested in the 1st reply, give the hotel a call and ask what it has/ what it can provide - or book a room that states it has 2/3/4 beds ( as required ) - or just book 2 rooms and see if the hotel can provide interconnecting rooms

You can expect the hotel to allow you to have 4 people in the room without charge - it does not mean that there would be no extra charge for additional items requested if the hotel is able to provide them

Have you spolen to the hotel ?