I loaded the latest version of BOINC 8.2.4. I've also loaded Docker. I admit that I am not tech savvy as most people in these posts, but what am I supposed to be doing with Docker, if anything? A clear set of instructions for non-programmer folks would be appreciated.

Do I need to be running Docker?

No. There are I think only two projects using it at all so far and I am not sure it is essential even for them, though there may be some task types you are unable to run without it. I think the plan, long term is to bundle docker with BOINC so there is no need for the end user to understand the intricacies of it. My main projects are very unlikely to use it for at least a few years so other than playing around in a VM to test stuff, I am not bothering with it. The advantage of it is that using it projects would only have to develop tasks for one environment (Probably Linux) and users of all operating systems would run the same tasks without having to bother with virtual box and installing a guest operating system.