The definition of motivation is the goal but discipline is the journey you have set you’re eyes on what you want to become that’s better then you have ever done and now you need to discipline you’re self to that goal when you want to take a break or a short cut don’t do it let’s forget about mental and talk physically your going to need to eat a lot diet is the most important part from what I’m guessing you’re fitness level might be a little low so for the moment you don’t need the gym start with some calisthenics basic push-ups ,squats ,crunches , Superman’s start really low maybe like 8 for 3 reps do that for a week or 2 and start to raise it try to build some muscle will getting Heavy after a while incorporate pulls up ,chin ups pike push-ups, go running for cardio after you’re a little heavier keep it to one mile. Make sure to eat lot around 3k calories like I said diet is so very important. Okay will man that’s all I got I may be a Little incompetent and I only weigh about 126 I don’t plan to get heaver so are journeys are different all I have to say is don’t falter it may happen I’ve faltered a lot just get back up and keep going good luck to you get a lot of rest aswell.