1) Do a search on the words "Yunnan college university english". That will give you the home pages of places that
hire foreign teachers.
2) Connect to said home pages.
3) Try to find phone numbers/e-mail addresses of English departments or Foreign Affairs Offices.
4) Send them your resume and a cover letter. You'll lose nothing by spamming them all.
5) Try the phone numbers listed. They may not be useful any more, but if you connect to someone, ask for the correct phone numbers.
6) If you don't yet have a WeChat (WeiXin) on your smart phone, get it.
English dept chairs and FAO officers all use it like e-mail or more.
If you don't read or speak Chinese, get a helper.
Some schools have English home pages, some don't. If you can make contact with an English speaking individual, send them your resume.
This is a good time of year to look, as some foreign teachers have quit/disappeared, and many departments/FAO offices are thinking about new feachers for the Fall semester.
Be persistent and flexible. China requires lots of can-do spirit!