What is the proper body gesture when greeting a guest?

It depends on the guest! And, it also depends on the situation and the time of day. But, physically, bowing is involved and for foreigners hand-shaking.

In some circumstances, they will be bowing and handshaking. In others, just one or the other. To give a better answer, it would be good to know more about the situation.

But, to be on the safe side, just a slight bow and a handshake will satisfy most circumstances.