user:install:manual:1.7.2:vanilla

The most important thing to understand when installing manually is that the version you create must have a consistent id. You must use the same id for every part of the installation process. In the example below we will use the id 1.7.2-LiteLoader1.7.2, if you choose a different id then you must alter this everywhere that the ID appears in order for the version to work.

installation steps

First navigate to the versions folder inside your .minecraft folder
Create a folder in versions with the id of your new version, eg. 1.7.2-LiteLoader1.7.2
Inside the new folder create an empty text file with the id of your new version and the extension .json, eg 1.7.2-LiteLoader1.7.2.json
Open the new file with a text editor and paste in the following JSON code:

{
    "id": "1.7.10-LiteLoader1.7.2",
    "time": "2013-10-25T14:00:00+01:00",
    "releaseTime": "2013-10-25T14:00:00+01:00",
    "type": "release",
    "minecraftArguments": "--username ${auth_player_name} --version ${version_name} --gameDir ${game_directory} --assetsDir ${game_assets} --uuid ${auth_uuid} --accessToken ${auth_access_token} --tweakClass com.mumfrey.liteloader.launch.LiteLoaderTweaker",
    "libraries": [
        {
            "name": "com.mumfrey:liteloader:1.7.2",
            "url": "http://dl.liteloader.com/versions/"
        },
        {
            "name": "net.minecraft:launchwrapper:1.9"
        },
        {
            "name": "org.ow2.asm:asm-all:4.1"
        }
    ],
    "mainClass": "net.minecraft.launchwrapper.Launch",
    "minimumLauncherVersion": 16,
    "inheritsFrom": "1.7.2",
    "jar": "1.7.2"
}

If you are using a different id, then you must change the value of id at the top of the file to match
If you wish to inherit from a different version, for example a version of Minecraft Forge, then change the inheritsFrom value to indicate the version to inherit from
- If you inherit from a different version, you must copy the minecraftArguments value from the other version and append: –tweakClass com.mumfrey.liteloader.launch.LiteLoaderTweaker
Save the file and run the launcher
Create a new Profile and select the version you just created.
Launch the game and liteloader will be downloaded and installed automatically.