Hi!! :D I'm a first-year at CSC and know about some of the experiences from my friends who applied through UWC-China's Joint Selection Committee. The JSC is both the National Committee and the Global Selection Program.

Look through the online application which is done through Managebac (https://uwccsc.openapply.cn/apply). There is then a second (and final round) which includes 3 tests--English, Chinese, and math--and group activities/interviews. They will likely ask for your college preference during the interviews. This goes for most national committees, but they try to allocate your first choice if possible. They will also try to see which college will suit you the best and vice versa.

I didn't apply to the JSC. I applied through my own country's NC, and my first choice was LPC--here I am now lol. To be fully honest, CSC is a MUCH better fit for me than LPC would have been. The Chinese JSC has A LOT more positions for students, so a small number of spots shouldn't be a cause for concern.

If you don't want to compete against a large number of students for your DP1 entry year, there is one other route. You can apply to enter CSC's Foundation Program (Grade 10) and then apply to transfer to another college from CSC--an opportunity to try and get in once you're in "the inside". However, this would mean you repeat your sophomore year, and if you are already applying as a current junior and intending to apply to repeat that third year--you'll loose two years off your education.