Open another terminal from the current one I am working on Terminal and attempt to create a New one with commands

$  open -a terminal


No feedbacks from the command

$ open -an terminal
The file ~/terminal does not exist.


How to accomplish it?
You have to separate the options and favor -n:

open -n -a terminal


This creates a 2nd Terminal instance!

If you add another option -F (fresh) you won't see any old/restored sessions:  

open -n -F -a terminal