to cast votes, you'd want to follow this: https://weibo.com/6013301829/NrCS7jFqE
1. first you need a the http://user.48.cn account (doesnt need to be real-name verified) as well as the codes from number one required for voting (buy from taobao, look for 点歌计分卡)
2. and log into https://b50.ckg48.com/web/songs.html and enter the codes (the website should be navigatable in google translate on desktop, if you need that)
3. then pick the song afterparty and pick yyq (袁一琦 )sys (孙语姗) and zym (张月铭) for h2, zjy (左婧媛) for teamx and xcw (徐楚雯) for teamz
4. afterwards, make sure you pick the exact positions (if not your vote will be void)
💛1号位 袁一琦 / #1 YYQ
💛2号位 左婧媛 / #2 ZJY
💛3号位 徐楚雯 / #3 XCW
💛4号位 张月铭 / #4 ZYM
💛5号位 孙语姗 / #5 SYS
5. then input the number of votes you want to spend on this and submit

this probably isn't a very good guide so you can also check the pictures in the weibo post linked above
if you have any issues with voting, you can also contact the yyh (https://weibo.com/u/6013301829) via dms on weibo or join 590043147 on QQ

hopefully this helps, once again thanks so much !