I had a good friend do this out of high school. Not sure what kind of guide you want to be. He went out west to Colorado, N Dakota, couple other states not sure where. He was a guide for elk and bear. Basically it went like this, he joined up with a guy that sold hunts. There were 8 guides total. 2 Guides went out at a time. They took the group up the mountain for no less than 7 days. Rode horse back, mules to pack the equipment. Once up, the guides did all the tracking,stalking, cooking, cleaning, ect.
In order to become this type of guide, you had to #1 have a good background with horses. My buddy worked on a horse farm for 6-7 years. He then had to go through guide school. It wasn't sitting in a class saying this and doing that. Guide school was in the mountains, living off the land for 30 days. He started with 9 people in his class. He graduated 30 days later with 2 people.
I am sure there is alot more to it that I am leaving out but this is where my friend started. He was just over a few weeks ago with this years pictures/stories. He did it for 6 years, this year being his last.