JW, the subject of getting a hamon has been extensively discussed on this forum. It isn't a process for beginners, and it will take some experience to get it down once you start.
It would take a lot more than a short answer to four questions to tell you what you need to know.I would suggest getting Walter Sorrells video on Hamons. It will explain every ting in detail.
I would get his entire series on Katana making...even if you never make a katana, you will learn a lot.
Some searches on BF, and an internet search on Hamon will also give you lots to read.