Adding cameras to my router C3700-100NAS

> I have a C3700 modem, [...]

   Modem+router?

> [...] My cameras are working, [...]

   Determined how, exactly?

> [...] but I can't access them on my computer.

   When you do what, exactly?  "can't" is not a useful problem
description.  It does not say what you did.  It does not say what
happened when you did it.  As usual, showing actual actions with their
actual results (error messages, LED indicators, ...) can be more helpful
than vague descriptions or interpretations.

> [...] They are Jennov POE IPC, [...]

   Is that supposed to identify a model?

> [...] running NVS software to be able to see it

   I don't know what that is.  Or what you're doing with it.