PLUGIN!

Hello i just started my new minecraft server. Everything is pretty much finished except for some plugins. One of the plugins being Factions plugin. I could not figure out how to install it for macbook. Some say to make sure i have Java 7, I need mcore plugin which does not work either, And i have seen some tutorials on youtube and people say to open Factions.jar And delete Meta-Inf folre. I cannot figure out how to open .jar on mac. If anyone could edit plugins or knows one that actually works with the Meta Inf folder pre deleted Please join my server and let me know (ip: FactionGames.no-ip.org) Or send me a private msg here on planet Minecraft.

Thanks for reading and I hope you could help me.