It depends on the mod and your OS, but...
Windows: Search %appdata% in your start menu, it should open up a folder titled Roaming. Go to AppData, then .minecraft, then bin. Open "minecraft.jar" with a program like winRAR or 7-zip. Now take the mod you downloaded, and drag all the files that are something like zx.class into "minecraft.jar". Finally, from "minecraft.jar", delete the folder titled "META-INF". Start Minecraft.
Mac: Go to (yourusername)>library>Application Support>minecraft>bin. Open "minecraft.jar" with a program like Zipeg or The Unarchiver. Now take the mod you downloaded, and drag all the files that are something like zx.class into "minecraft.jar". Finally, from "minecraft.jar", delete the folder titled "META-INF". Start Minecraft.
Ok, thank you, but this is the point. I don't get it very much. You have to download so much!
Ok, thank you, but this is the point. I don't get it very much. You have to download so much!
Basically, you download whatever you need (The mod, ModLoader, etc.). You unzip it (It should come in a ".zip" file) and there should be tons of files like sf.class, which you need to drag into "minecraft.jar".
oh.
how do you install mods? I tried looking for it on youtube but all the directions are messed up.