Hello.
This works on most Samsung phones. Open Contacts with the icon.
Make sure Contacts is highlighted on the right of phone, groups, favourites, Contacts.
Below is a search window and to it's right a + box. Touch that enter your details and remember to save.
You will have a choice of where to save with a drop down box. It's normally set to Device (phone), but you can save to sim card (limited space) or your Google or Samsung account. If you save it to device, you can sync or merge contacts with your accounts later.