Where can I find information about the Joint Combined Warfare School-Hybrid (JCWS-H)?

Allocation of slots is usually announced by a MILPER message.

You can contact your applicable POC at the following and get the answers directly from them.
https://jfsc.ndu.edu/Academics/Joint-and-Combined-Warfighting-School-JCWS/JCWS-Contacts/

Not I.

In 2016, Joint Forces Staff College completed the transition of the older Advanced Joint PME blended (AJPME) program, which granted "JPME II equivalency" but not ACTUAL JPME-II status required by statute for Regular Component officers to be qualified for promotion to general officer, into the Joint Combined Warfare School-Hybrid.

As JCWS-H is fully JPME-II qualified, it meets the requirements for both the Regular and Reserve components to deliver the necessary Joint PME.

Each Service receives quotas for each of the JCWS-H classes each year (probably several a year going simultaneously asynchronously), so you must ask your Service for the appropriate solicitation/message traffic, or ask a career detailer as the Service may select attendees without officer requests.

I was one of the first US Marine reserve officers to complete the then-new AJPME program in 2006, and found it very timely and useful. I'm certain it's even better now, as the JFSC has had 15 years to improve it.

See: https://jfsc.ndu.edu/Academics/Joint-Continuing-and-Distance-Education-School/AJPME-Overview/#:~:text=AJPME%20was%20formally%20changed%20to%20the%20Joint%20and,JPME%20II%20status%20upon%20completion%20of%20the%20course.

Cheers, WKB