Once in APN hit the “kebab setting menu”(three vertical dots on the top right) then hit -Reset to default
My phone had a Koodo and TELUS APN settings come up, ignore them and hit the“+”(top right with a circle around it) and then manually input the following APN settings (please make sure it is all exact even upper- and lower-case letters):
Name: Public Mobile
APN type(select each one): default, mms, supl, wap, net
Nice post. Did your data not work previous to you editing the APN? Is your phone CPU? Samsung phones normally populate the appropriate APN after inserting the sim card. Often the APN will list telus or koodo as the provider but the APN will still work for public mobile.