It helps if you know a girl personally who is willing to do a porn scene with you. You will have a better chance at getting more work if there is someone you know rather then trying to enter the industry on your own. Plus you have to be willing to go to an agency and pay expensively for a portfolio. It's optional unless you want to do your own fully nude portfolio but you will be better known if you do it professionally. That includes taking photographs of fully nude shots of yourself, pose like a model, maybe even with another male model becuase after all you are selling yourself. It's basically the whole nine yards. The people at the agency will tell all the details for you in advance but when you sign up just remember once you get a paycheck half of that goes to the company.
Also just another heads up but do not expect to make a lot of money right off the bat. Male pornstars get paid far less then female pornstars. The male adult stars also get treated far less then the women but you won't know unless you become a performer yourself and witness the ups and downs in the industry. Also you have to be willing to work 8 to twelve hours a week and be ready to cum on set. If not, you and your co-workers may not get paid so it's important you can achieve the film director's wishes. This is why some adult stars (men and women) get into *****. It's their way of staying "hyped up" and to prepare them so they're ready to do a scene but like always, getting into ***** is dangerous so becareful. The adult industry is not a one woman fuck, get a paycheck, see ya. You actually got to work tirelessly for your money and take a lot of **** from the film crew as well. Unless you set up your own porn production company, then you can basically call the shots.
As soon as you've been getting more work (by then you'll have an agent but some of them act like pimps since they are just looking to take advantage of their clients rather then boosting their careers) you'll be able to find out what areas you like to work in the industry and areas and studios you don't like to work for. If you ever meet a pornstar and you ask them what does it take to get into the adult film world and they tell you to do some research before entering. They are mostly telling you the truth.
Hope that helps or makes sense...