1. rename jar file to the name you want
2. rename .json file to what you want
3.chang the id in the file from "versionhere" to jar file name

{"id":"versionhere","libraries":[{"name":"net.minecraft:launchwrapper:1.6"},{"name":"net.sf.jopt-simple:jopt-simple:4.5"},{"name":"org.ow2.asm:asm-all:4.1"},{"name":"net.java.jinput:jinput:2.0.5"},{"name":"net.java.jutils:jutils:1.0.0"},{"name":"org.lwjgl.lwjgl:lwjgl:2.9.0","rules":{"action":"allow"},{"action":"disallow","os":{"name":"osx","version":"^10\\.5\\.\\d{param}quot;}}]},{"name":"org.lwjgl.lwjgl:lwjgl_util:2.9.0","rules":[{"action":"allow"},{"action":"disallow","os":{"name":"osx","version":"^10\\.5\\.\\d{param}quot;}}]},{"extract":{"exclude":["META-INF/"]},"name":"org.lwjgl.lwjgl:lwjgl-platform:2.9.0","natives":{"linux":"natives-linux","osx":"natives-osx","windows":"natives-windows"},"rules":[{"action":"allow"},{"action":"disallow","os":{"name":"osx","version":"^10\\.5\\.\\d{param}quot;}}]},{"name":"org.lwjgl.lwjgl:lwjgl:2.9.1-nightly-20130708-debug3","rules":[{"action":"allow","os":{"name":"osx","version":"^10\\.5\\.\\d{param}quot;}}]},{"name":"org.lwjgl.lwjgl:lwjgl_util:2.9.1-nightly-20130708-debug3","rules":[{"action":"allow","os":{"name":"osx","version":"^10\\.5\\.\\d{param}quot;}}]},{"extract":{"exclude":["META-INF/"]},"name":"org.lwjgl.lwjgl:lwjgl-platform:2.9.1-nightly-20130708-debug3","natives":{"linux":"natives-linux","osx":"natives-osx","windows":"natives-windows"},"rules":[{"action":"allow","os":{"name":"osx","version":"^10\\.5\\.\\d{param}quot;}}]},{"extract":{"exclude":["META-INF/"]},"name":"net.java.jinput:jinput-platform:2.0.5","natives":{"linux":"natives-linux","osx":"natives-osx","windows":"natives-windows"}},{"extract":{"exclude":["META-INF/"]},"name":"net.java.jinput:jinput-platform:2.0.5","natives":{"linux":"natives-linux","osx":"natives-osx","windows":"natives-windows"}}],"mainClass":"net.minecraft.launchwrapper.Launch","minecraftArguments":"${auth_player_name} ${auth_session} --gameDir ${game_directory} --assetsDir ${game_assets} --tweakClass net.minecraft.launchwrapper.AlphaVanillaTweaker","minimumLauncherVersion":7,"releaseTime":"2009-12-22T08:30:00+10:30","time":"2013-08-07T00:03:30+09:30","type":"old_alpha"}