http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/1285818-schematica Go to that link and download the core files required for Schematica. It's called like Lunatrius Core.
When you say opening...? I believe you just put both files in your appdata/roaming/.minecraft/mods folder. Once you've signed into your forge profile and joined a game, I think it uses the /, *, and - keys on your number pad as menu keys for the mod.