I wrote an NIH project for my professors while discerning my dissertation for my PhD. For TB it's simple. Find a successful TB NIH project on-line as a model how to write your TB proposal. Do not plagiarize! Since you are not in a US university, I assume, you shall require a US Professor, preferably of Associate Professor status or above, to act as project director, with you listed as an assistant in co-authoring the project, even if you do all the work. You need a Professor who is published in the field and preferably has been approved previously in a successful NIH project. Here are some initial NIH links to read through - remember that authoring a successful NIH application for a project requires at least three to six months before it's ready to send to NIH, and it all depends on you having a published director of high status, plus other published professors, usually in the US, supporting the project:
your average international (US+another country like Nigeria) project requires three years, and is stronger if it includes a third country for comparative application of treatment results and diagnostic methodologies. The first year is organizing everyone and the site/s, second year is pretty much dedicated to testing the theory, third year is dedicated to verifying results and publication. A good project anticipates that the theory is successfull in the third year for publication and thus a clause is written in the original NIH application providing for further annual renewal of the project funds after the first three years :) thus you aim at a minimum of 250,000$ per year for a successful project. Anticipating the after three year clause should be written so that you are happy to close the project at three years, unless the project is so successful that it should be renewed if NIH desires this - do not look money hungry and communicate that it's NIH's project and for them to decide. A good proposal author who is involved in the researcher can easily earn $15,000+ annually from the annual $250,000, and the income goes up if you can eventually direct the project yourself, replacing the original project director - thus if you live in Nigeria it's a secure way to establish your career as a researcher and worth the three to six months writing out the NIH application.