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The S7 like the S6 should by default be able to see your router without any issues. However, it is possible you might have it in Airplane mode. Do you know how to check that?
Are you able to see other routers outside of your own? Say if you were to go to an inet cafe?
When was the last time you rebooted your router? And is it a modem and router in one?
Okay, then I would run it to your local store where you bought it and ask them to replace it. It seems to me that something is wrong. Does it see your router and does not accept the password ***** simply does not see it?
Since it is so new and most likely not much else on it I would think. You could try to do a factory reset?
Factory reset Galaxy S7 or S7 edge the easy way
But only do this IF you have nothing on your phone like pictures and such that you do not want to lose.
Something else to look for...
There has been multiple reports of all sort of wifi issues happening affecting different phones not just the S7/edge, and for the most part it has been fixed by forcing the wifi router to use just IPv4 and disable IPv6, check your router to see how you can force that.
Please let me know the status of your phone and if all is working please remember to accept my answer and rate the support I have given. If there are still issues then reply and let me further assist. Thanks in advance.