Go to the website
Air Nigeria - AN Careers and download the application form then fill it and send it in.
Remember, only the best need apply.(thats what the website says)
Depending on your experience level, you'll be invited for an assessment.(hand-eye coordination, arithmetic, instruments interpretation)
If you pass the assessment, then next stage is interview.
If you fail but have a relevant type rating, you'll be invited for a make up test.
If you pass the make-up test, you'll be invited for an interview.
The interview is quite short, questions are asked based on the way you answer your first question. plate briefing is a given.
If you are successful, then you get offered employment.
Good Luck
DISCLAIMER: I DO NOT REPRESENT AIR NIGERIA IN ANY CAPACITY