You do not need to set up any settings for original carrier, everything will work out of the box. To get apn settings for your carrier please contact your carrier or search online.
If it says specific carrier then it can only be activated with those carriers. Do not assume that it will work with your carrier unless stated. The item "New Other Samsung Galaxy S9 G960U G960U1 Unlocked AT&T Cricket T-Mobile Verizon" is in sale since Wednesday, January 16, 2019. This item is in the category "Cell Phones & Accessories\Cell Phones & Smartphones". The seller is "mobileitems" and is located in Deerfield, Illinois.This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Brazil, Costa rica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, Turks and caicos islands, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Ecuador, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Pakistan, Paraguay, Reunion, Uruguay.