well in order to work with a broker you have to have your own authority.
you can pay someone to get it for you or you can go here
Registration & Assistance: USDOT Number/Operating Authority - Federal Motor Carrier Safety Administration
just click on the link for registration and updates fill out the form and pay $300
you will also need process agents so someone can sue you even if they dont have your address.best I found is rex $30 for the lifetime of your company.also he will provide you with alot of information
Process Agent Service - only $30 | Evilsizor Transportation Services
now it takes 2-3 weeks for you to get your number
you will also need insurance both primary liability and cargo
1 million liability and get at least 100,000 cargo
once you get your number and insurance depending on gvw of the trucks you run you may have to set up an ifta account to pay fuel taxes if your over 26000 gvw
and you may need an irp account this is so every state your gonna travel in gets a chunk of your registration fees.
if you tell me what state your from I will give you phone numbers or web addresses of who to contact.
its a piece of cake as long as you dont mind keeping good records and if its your dream to build a company just do it but consider yourself warned its easy to get into and easy to go broke tring to keep it running.