How do I change my baby boy's diaper?

It's OK if it works! I'm assuming you're asking about a cloth diaper? If so, fold the diaper so you place extra padding over the penis to catch the urine. Fasten it at the baby's hips with tape - or with diaper pins if you're brave. Disposables are probably easier to use, especially if you are new at this! remember, it only matters that it works - not how it looks! good luck.
Carefully! Boys and girls have the same diapering requirements and use the same diapers. The only difference is boys can aim! never leave your baby on a changing table, even for a moment. Lay them down, open their diaper, hold their feet up and wipe their bottoms. Remove the dirty diaper and place a clean diaper under them. Use some barrier ointment to protect their skin, if desired, and seal 'em up!