Our play has [as its theme] how Hong Kong people successfully govern Hong Kong as a special administrative region that enjoys a high degree of autonomy.

The how clause is a nominal clause here used as the object of has. It is placed after “as its theme” because it is very long.

administrative

administration行政、管理

administrate管理、执行

autonomy: freedom to govern a region自治权

autonomous自治的、自主的

full-length: adj. (of a play, book, etc.) not short; not shorter than is usual未删节的 rehearse排练

n. rehearsal