I am looking to better understand how self directed IRA works

[Lucas Milburn]

I currently own 3 STR properties and am currently applying for a HELOC against one that I own outright. In addition I have heard a couple podcast on BP referencing self directed IRA's. As I look to grow and purchase more properties I plan to bring on investors and wanted to better understand the concept so that I may better explain how to do it and how it works to potential investors as a source for them to draw from. Any info or good links to resources on the matter are greatly appreciated.

Thanks