Well, welcome to the wonderful world of HMDA.
To answer your question, I should ask: Are you required to report for 2019, or will you start collecting in 2020? Either way, you may want to get some outside assistance to get caught up on the complex world of HMDA. If you must report for 2019, you are going to be significantly behind the curve and I would highly recommend hiring someone to do they best they can to catch you up. If you will be reporting for 2020, I would start the learning process today and recommend taking a class/a few webinars on HMDA (BOL offers several in their store). Even for small filers, in-person seminars can easily take a full day, and that really doesn't cover all of the quirks that can come with HMDA.
In addition to using training to fast track you to getting caught up, I would highly recommend that you become familiar with the documents Melissa S provided. These resources are a bit easier to chew than the regulation itself, but you can always view the regulation (and commentary) here:
https://www.bankersonline.com/regulations/12-1003-000 Finally, as you have questions on HMDA, feel free to post questions here as there are many BOLers willing to help you out - since we all love HMDA so much.