The archive you need to mess with is the equivalent of the minecraft.jar file executed by the various clientside launchers. The server version may not be called exactly that; I'm not familiar enough with it to know. But it will be a jar file; probably the only one that came with the server files.Thank you very much for responding so far.
Sorry I don't understand much of what you're saying. The minecraft.jar you mean is the minecraft_server.1.7.10?
Also the forge would be the forge-1.7.10-10.13.4.1558-1.7.10-universal?
Thank you in advance.
Windoze Explorer has an annoying "feature" where it won't, by default, show file extensions. I strongly recommend disabling that if you're going to do anything nearly as advanced as messing with zip files. I do not know how to do this; it's one of the reasons why I avoid using that operating system whenever possible.
And yes, you will need to download the very same Forge jar file as you normally would when installing it manually in a vanilla client. Do not copy files from Forge's installer application (if it's an executable jar; I don't remember if they use jar or exe); that will break things.