Why there is no manual proxy in lubuntu?

How to set up a manual proxy for lubuntu. For some reason my wifi is at a distance that my pc can’t connect to. So i used netshare to share it in windows. Linux is not supported but I can use proxy to use it and am currently using as well through firefox. But I can’t install any programs using Discover maybe because it is not in the system proxy but just the firefox proxy.

Now I found out that right clicking on the wifi selection button then edit configurations then going to the wifi and then proxy there is an option. But there is no option for manual proxy. Just None and Automatic is present. How to set it up cz unless that I can’t use it for anything.

I don’t know if this Ubuntu solution works, but it sounds similar.
Apparently, you select ‘Automatic’ and type in a file:///etc/proxy.pac as the PAC URL.