what do additional statements in the trademark application mean? Which ones do I need to check off?

If you're using the TEAS online filing system, the terms like "additional statements" are explained. They refer to disclaimers, translations, explanations of things that aren't obvious from your mark, etc.

Yes, you really need them. You need to fill out this application correctly or it won't get approved. Anything you don't get right and don't conform to the way your assigned trademark examiner --your "judge" for this process-- is used to seeing in applications will result in an "Offfice Action" response not sent for several months, and giving you 6 months to reply to. In other words, mistakes are very costly in terms of time, because each mistake means your trademark isn't getting registered. Do yourself a big favor and hire a lawyer to help you to avoid missteps.

Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.

I agree with Ms Koslyn - hire an attorney. You *might* be able to get through the application process on your own, but I guarantee you that the first Office Action you receive will trip you up. If the product is important to you, then hire an attorney and get it done correctly.

The additional statement section can refer to a number of different issues. The Examining Attorney may have requested a disclaimer of a term, a description of the mark (including color claim and/or stippling statements), a claim of prior registration(s), translation/transliteration , meaning and/or significance of wording, letter(s), and/or numeral(s) in the mark , Section 2(f) claim , Consent to register name(s), likeness(es), signature(s) of individual(s), or amendment of a mark to the Supplemental Register. Do not confuse "Additional Statement" with "Misc. Statements". which are matters not covered by "other areas" in the online TEAS form. The miscellaneous statement field includes the ability to attach a file, for example, to provide requested product literature.