The common purpose of nursing home visits is to raise the morale of the people staying in these institutions and to prevent them from feeling abandoned.
Old-aged homes need volunteers.
The visit by volunteers prevents them from being deprived of the attention.
During the nursing home visit, the only thing that elderly people expect from volunteers is that they sit down, listen to them, and talk to them.
If you want to go to visit them you can buy them small gifts, this is another detail that will make them happy.
You do not need to make too much preparation for the nursing home visit. It will be enough to be very understanding of elderly people during the visit and to be careful to listen to them while they talk.