Hi, I'm Nathan.Sorry to hear that you're having trouble with this but I'll do my best to help you.
Are you trying to view the cameras locally (monitor attached directly to the dvr), or remotely (computer, phone, etc)
You do need to be signed in with administrative rights to be able to change any settings.
Are you simply trying to view the cameras, or do you need to change something?
I am here, but please send only a single message and give me a moment to respond. When you send multiple messages they can get further delayed/lost and it takes me longer to get them.
You have to actually sign in as the user with admin rights or you can't change anything,
the default should be "admin" for the user, and 1234 or 123456 for the password, depending on the model, and assuming you have not changed the default to something else.
Do you need more help with this?