This can be found on 58. You want to open the page of 58 cities, and click Switch Cities in the upper left corner of the homepage:

Open this page and click Lanzhou.

After entering this page, enter "restaurant waiter" in the red dialog box and click search in the same city.

Enter the following page, and you can choose any position, region and welfare in the red box marked by me.

Pull down the mouse. The following are the companies that need to recruit waiters in Lanzhou. You can click to enter one by one. There are contact information in it. You can call for advice.