Potential employers will often ask for your references. These are people who have worked with you in a professional capacity, and can vouch for your skills and personal qualities. These are ideally former bosses or commanders, but can also be colleagues, if you feel they have a relevant perspective on your professional abilities. Obviously it’s important to choose people who have a good opinion of you!
It’s best to have more than one reference, but 3 or 4 are usually enough. When you have people in mind who you think will be good references, ask them if they’re willing for you to give their name to your potential employers, and if so, which of their contact details you should pass on. If some time has passed from when you last spoke to your references to when they might be contacted, do them the courtesy of letting them know they might be called by a certain employer.
Don’t include your references in your resume. When going to an interview, have a printed list of your references and their contact details on hand, to give to the interviewer if asked.