pretty much this but also how to train physically and how to train mentally are important questions. my personal recommendations for physical training would be going to MMA classes as much as possible although in some areas they can be expensive. you can go to a cheap pozzed gym like planet fitness to go along with your mma classes. if you can afford it it'd be better to own your own workout equipment. if youre never going to go to a gym then at least do bodyweight exercises which can be easily looked up on the internet. yoga is a good way to exercise the mental and physical.
As for mental training keeping a regular workout routine and MMA routine will do a lot, but theres still more you can and should definetly do to at the very least avoid slipping to a state of degeneracy. Live an ascetic lifestyle where you are materially minimal. avoid for yourself the best comforts and the best pleasures. be very clean in your own body, and your home. live as simply as possible with as few possessions as possible. this is VERY powerful for your mental stamina and mental sharpness.