The Basic Medical Department Officer Course (BMDOC) is offline until spring 2020. You normally do it because it is a prerequisite for the Advanced Medical Department Officer Course (AMDOC), which was recently renamed the Advanced Readiness Officer Course (A-ROC). Until it is is back up, you won’t need to do it to attend A-ROC, the artist formerly known as AMDOC. Here’s the full memo:
The instructions to sign up for A-ROC are in this document.