This book has a nice summary that will keep it simple. I've been using this for a year now and it's shown me how motivation can be aimed and corrected. Looking into Buddhism and perception was also very helpful in seeing how these mental worlds in our mind create affect which essentially makes the choice for us. There's a lot more in the book regarding the types of beliefs that are very popular and destructive:

Want to vs Have to

Bad vs Awful

Difficult vs unbearable (low frustration tolerance)

Self-acceptance vs self-damning

REBT

Summary of CBT Process of change and goal accomplishment

Current Position: Your unhealthy belief and 'what's in it for me' in keeping it i.e. Nothing. Thoughts, feelings and behaviour are then compromised.

1. Think constructively with your healthy belief.
2. Challenge your unhealthy thoughts triggered by your unhealthy belief. (Old mental habits arising)
3. Remind yourself why you want your healthy belief and goal in order to help yourself tolerate the discomfort of stretching beyond your comfort zone. Remind yourself why your unhealthy belief is unhelpful.
4. Act in accordance with your healthy belief and remind yourself why you are doing it. Apply Step 3.
5. Repeat steps 1-4 in an energetic and forceful way.
6. Overcome obstacles caused by other unhealthy beliefs as and when you encounter them during the process until...
7. Your feelings change - this happens last.

You may not achieve your goal while doing this but you have a much better chance of doing so with this mental framework than the habitual negative beliefs, plus doing this often enough will change habits.

When using meditation it's good to notice the feelings in the body (vedana) because that will often tell you what belief is operating when you hit an aversion roadblock making you act the old way.

So I've created a mnemonic to remember this so it's ready in real-time when aversion strikes.

1. A Construction guy
2. eating unhealthy food
3. stretching his waste-band
4. making him act nauseous
5. and then repeatedly vomits
6. on an obstacle course
7. until he feels better.