Nowadays the best start would be probably things like chaturbate, manyvids, onlyfans and might even need some investment in the beginning (if you wanna do straight porn). Will be a slow start but getting hired by an agency as a male pornstar ain't as easy as it is for women. Another possibility could be gay4pay but it's not 100% safe you get into straight porn. Joining porn as a couple is another way. Basically if you don't know anyone in the business it will be hard.