External proxy server

How I can redirect traffic on port 80 from my routerOS to another external proxy serwer. Thanks for help !!

Setup proxy on your router, then specify ‘parent-proxy’ in proxy configuration to redirect proxy requests to upper proxy.

Thanks
I have one question?? Proxy work with only one adsl line ?? I have two adsl line for http proxy. How I must configure it
Thanks for help

configure it that way, that you can reach proxy and proxy is actually accepting connections from possible your child proxy