Have you tried looking in the tutorial section?
https://www.mpgh.net/forum/forumdisplay.php?f=40
https://www.mpgh.net/forum/showthread.php?t=640873
https://www.mpgh.net/forum/showthread.php?t=707962
https://vasco-gfx.deviantar*****m/art/...rial-128401604
https://platinification.deviantar*****...F32703793&qo=4
https://beintelligent.deviantar*****m/...rial-261123006
Those are all signature tutorials, but you can find plenty of general photoshop tutorials online, especially places like Deviant Art.