Transitioning from Active Duty to the Reserves as a 66H

I’m an active-duty Army nurse (66H) and my active-duty commitment is up in August 2029. I don’t think I want to stay active duty after my commitment is over, but I’d definitely be interested in transitioning to the Reserves.
For those who have gone from active duty to the Reserves, how does the transition actually work?
My biggest concern is making sure I can find a Reserve unit/billet before my active-duty commitment ends. How far in advance should I start looking, and who should I be talking to (career counselor, retention, HRC, Reserve career counselor, etc.)?
A few things I’m particularly curious about:
Do I need to find and secure a Reserve billet myself before separating from active duty?
How early can I start the process?
Is there a specific process for an active-duty 66H to transition directly into the Reserves?
How difficult is it to find a Reserve nursing position, especially if I want to stay in the same general area?
Is there anything I should be doing now to make the eventual transition easier?
If anyone has made this transition as a nurse, I’d love to hear how you handled it and anything you wish you had known beforehand.
I have plenty of time before 2029, but I’d rather understand the process now so I’m not scrambling when the time comes. Thanks!