In answer to your question.
An exerpt from "TheFryingDragon" posted in this web site about the basic points of contact. Full text can be found in:
https://www.ballroomdancers.com/Message_Board/view_messages.asp?MsgID=9153&PageNum=1
"...To lead properly in closed position (smooth/standard) requires a good understanding of the five "points" of contact. These are: (1) the man's left hand w/ lady's rt. hand, (2)rt. palm around the lady's left back (scapula) area(allowing for height and so on), (3)right forearm (under ladies left upper arm), (4) lady's left hand on the man's right upper arm (below the deltoid) and (5) the body.
The combination of these points form the basis of the language that the lady must listen for, interpret, and execute--factoring the general direction of movement as a couple, swing, balance, and so on. Sometimes you can omit words in sentences and still convey the proper context of the message. Thus with just one point of contact you could lead a lady into a turn. Leading is simply communication. Good communication requires good sentence structure. Word choice can make a sentence elegant and supremely understandable. Sloppy words create garbled messages. Same thing. For instance, holding the left hand/arm correctly makes it easy to follow."