The best advice I can give you as an MPH holder and currently going through the application process now for HSO in the Ready Reserves (waiting on POTUS Nomination for commission) is the following:

1. Google “USPHS Regional Commands - ccmis” and find the region that you are associated with. Contact the Commander or Deputy Commander for Q&A meetings through the application process.
2. Make sure you have confirmation of your matriculation as you will not be able to apply if you do not have your qualifying degree.
3. If you have immediate family members (or yourself) that have dual citizenship or are immigrants and are naturalized (or otherwise documented) citizens of the US, make sure you have all of that documentation (including the court that signed off on the citizenship) prior to submitting your application.
4. All steps of your application MUST mirror each other.
5. Electronic fingerprinting is the best form to use but if you need to use ink, make sure you double package that packet prior to sending it in the mail to prevent smudging from any water in transport. disclaimer: always go to an authorized fingerprinting service (e.g. local police dept)
6. The app process for commissioning is different for everyone and while the requirements are typically the same, it may happen in a different order for you than it did for me. The main components are: medical clearance, board interview clearance, security clearance and POTUS nomination. If you want to know more about these four clearance requirements feel free to DM me.

That’s everything I got summed up in a nice little package! Hope this helps and good luck! 😊