The truth is that all boys develop at different rates. It depends on the release of hormones such as testosterone.
There is a scale called the tanner scale, which medical professionals use to determine the rate of development in pubescent males.
You can find more about that here.
Rather than specific stages, I'd say there are "signs" that a boy is going through puberty, and there are several "checkpoints" he should expect to go through.
The stages of puberty in males
1) Increased body odour
2) Increased testicle size
3) Increased penis and scrotum size
4) body hair growth
5) enlarged pectoral/chest muscles
6) acne and other mild skin conditions
7) increased frequency of erections
8) occurence of wet dreams
9) growth spurt
10) Jawline and shape of face changes
11) Deepening of voice (cracking voice)
12) Increased attraction to opposite sex
13) moodswings, anxiety, and other emotional changes
Going through puberty is tough, so good luck!
