I hope the dealer gave you the operating manual when you received your machine. The Back Hoe manual will tell you how to remove/dismount the BH. I removed mine for the first time a week ago and it took just a little over 5 minutes. Most of that time was figuring out where to put a few pieces of 4x4 wood for the BH to rest on. I have the Kioti KB2375. Which brand and model do you have? If you don't have the manual, I'm sure someone here that has a similar BH, can give you a condensed version of how to remove.
Kind of hard to explain "everything" about the 3pt and how to set up the brush hog in this forum but the members could try. Do you have the brush hog attached? What type is it? I'd stop and talk with your dealer or find a neighbor who has some experience. Maybe ask specific questions about what you need to know.