Let the school know you're thinking of applying — they can share their prerequisites and help you through the process.
It's best to ask — circumstances can change at any time.
Beijing Royal School (北京王府学校) was established in 1996 and is described on the school site as Beijing's first Sino-foreign cooperative school; it introduced A‑Level and AP courses in the 2000s and holds IB authorization. The campus is described as sitting north of the Beijing Olympic Village, on a 150-acre site with extensive teaching, sports and residential facilities, including a multilingual simultaneous-interpretation auditorium and a dedicated student apartment (boarding) area. The school lists signature international activities such as a “Future Diplomat” project and cooperation with international organizations, and notes both dedicated school buses and on‑campus boarding arrangements. Recent published annual tuition bands on the site show primary-to-high-school and kindergarten fees (the site lists kindergarten fees by month and senior‑school fees by year). All items above are taken from the school website.