I hate to say it but I don't know grammar rules well enough to explain it. The best I can offer is something that sounds better to me. First example is the paper, second example is one possible rewrite:

"The first order of business will be to draw some distinctions between these notions and pick an appropriate focus for our present inquiry. That is the aim of section 1."

"Section 1 draws distinctions between these notions, one of which will be the focus of our inquiry."