Contact a service organization at your local VA. Talk to them about your possible claim. Find one you like and file a claim.
They work your case and you don't pay them a dime. They are paid to work your case through separate funding.
What you provide is all the documents for your claim and a statement basically laying out your case from A-Z for each military related injury you are claiming.
If you are successful in obtaining a disability rating you will be back paid to the date of your original claim date. Any disability money you receive is state and federal tax free. With a disability rating you can also be entitled to other VA provided benefits.
I have successfully steered several vets through the VA disability rating process. It's not that hard, it takes time but in the end you can be compensated for injuries you incurred in the line of duty, Why not sign up and see what happens,