You are picked up at Polaris World HQ and driven in a minibus to Murcia city.
Then they take the paper work into the NIE office while you get a coffee.
Come back half an hour later, bypass the long line of people who have been there for hours, (and think you have jumped the queue) and collect your NIE.
Be careful and check your details are correct. My wifes details were fine, but when checking again later I discovered one letter wrong in my name, and had to come back the next day.
However better that than finding out at the completion.
Good luck.
J&P