I couldn't agree more with his point. Think of this from an athletic perspective. If someone wanted to learn how to pole vault, wouldn't it be ridiculous to give this beginner a long pole, set the bar at the current world record level and then tell them to run very fast and get over the bar? How much success would they experience? How long until they gave up and said it was impossible?
Wouldn't it maybe make more sense to give this person something that they can achieve, no matter how small? Maybe give them a 3 foot long pole and ask them to flip over that pole onto a nice soft mat, so they can learn how to flip over the bar. There must be some beginner activities that can be used to allow a person to gradually work up to being able to break the world record.
BTW, even world record breakers generally use the same approach. I have never heard of world class athlete structuring their workouts where they start by giving themselves the largest possible challenge and then just keep trying to achieve that result. Instead, they almost always start with something that, for their current abilities is almost certain to lead to success. This is sometimes called a warm-up. After the warm-up, they will then gradually increase difficulty until they are ready to attempt the world record levels.
So when it comes to other areas of your life, use the same idea. Set some warm up goals. What are some goals, that at your present level of ability, you are almost certain you can achieve them. As Lewis says, think small. Maybe your first goal is just to get out of bed. That's fine. They key is that once you achieve your first goal, celebrate, and immediately set another goal.
Keep raising the bar like this and congratulating yourself. If you hit the bar and knock it off, that's great. This is what is going to happen and every world class athlete knocks the bar off every so often. Just reset the bar, set a new goal, maybe a smaller goal if you want, and go again. Develop momentum and soon you will be amazed at how high the bar is.