As you know IFTA filing (preparing documents connected with how to get CDL) can create a lot of troubles. Fortunately you are not alone. First thing you need to do is to ask some people for help. If you don't know anybody who is experienced in IFTA filing, you can hire a special firm, but in my opinion it's an expensive option. I think it's better to use the net. There are many websites that can help you to calculate your tax.