Ok,
1.Book an appointment online with the Spanish embassy in Merlyn Park D4.
2.Fill in form Ex-15 .(just the first 2 pages) and print it out.
3.Fill in form 790 code 12 and print it out.
Make copies of the information page of your passport and your driving license to prove your address.
4.Present yourself at the embassy (17 A Merlyn Park Ballsbridge).
Sign the documents in the presence of the official,pay the €9.84 fee in cash and they will email you a PDF of the NIE approval in 3 weeks or so.