• You can download MultiMC from their website. See their instructions for how to install MultiMC on your Operating System.

1. Open Impact Installer (see Setup FAQ if you have issues)
2. Select Install for: "MultiMC Instance"
3. Use Browse to select your MultiMC install directory
4. Choose the Minecraft/Impact version combo you want (latest is recommended)
5. Select if you would like to include OptiFine in your Impact instance
6. Click "Install"

1. Open Impact Installer (see Setup FAQ if you have issues)
2. Select Install for: "Show MultiMC JSON"
3. Choose the Minecraft/Impact version combo you want (latest is recommended)
4. Click "Install"

5. A window will appear saying "Here is the MultiMC JSON...", click "OK"

6. Somewhere else on your screen will be a window containing a bunch of complicated looking JSON code. You'll need that for step 3...

NOTE: You can use Ctrl+A followed by Ctrl+C to copy the generated JSON code

1. Open MultiMC
2. Create a New Instance using version the corresponding minecraft version, choose a memorable name, e.g. Impact 4.8.3
3. Right click on instance and click Edit Instance
4. Go to the Version tab
5. Click Add Empty
6. Choose an appropriate name, e.g. Impact 4.8.3 for 1.12.2, and exact uuid: net.impactclient.Impact
7. Select Impact 4.8.3 for 1.12.2 (or whatever you just typed) and click Edit on right side
8. Type Ctrl+A and Del to remove any exiting contents
9. Paste the JSON content generated earlier by Impact Installer:
   • Click on the window (containing generated JSON code) that Impact Installer opened earlier in Step 2
   • Enter Ctrl+A and then Ctrl+C to copy the JSON code
   • Click on the window MultiMC just opened to edit your new version entry
   • Enter Ctrl+V to paste in the generated JSON code
10. Save the file
11. Click Run and you should see Impact launch 😃

Impact Installer's optifine json not working so set optifine version to none

1. Have Minecraft 1.14.4 installed on the default MC launcher.
2. Run the OptiFine installer and extract, then move the extracted JAR to your instance's libraries folder and remove the "_MOD" suffix from the filename.
3. Run the OptiFine installer again but now Install OptiFine for default MC launcher.
4. Go to %appdata%.minecraft\libraries\optifine\launchwrapper-of\2.1 and copy the JAR to your instance's libraries folder.
5. Go to the Version tab for your instance in MultiMC.
6. Add Empty
7. Name: OptiFine
8. uid: optifine.Optifine
9. Edit it
10. Paste the following into the file (if your optifine version isn't same change line 13, 15 and 27 )

{
    "+tweakers": [
        "optifine.OptiFineTweaker"
    ],
    "formatVersion": 1,
    "libraries": [
        {
            "MMC-filename": "launchwrapper-of-2.1.jar",
            "MMC-hint": "local",
            "name": "optifine:launchwrapper-of:2.1"
        },
        {
            "MMC-filename": "OptiFine_1.14.4_HD_U_F5.jar",
            "MMC-hint": "local",
            "name": "optifine:OptiFine:1.14.4_HD_U_F5"
        }
    ],
    "mainClass": "net.minecraft.launchwrapper.Launch",
    "name": "OptiFine",
    "requires": [
        {
            "equals": "1.14.4",
            "uid": "net.minecraft"
        }
    ],
    "uid": "optifine.Optifine",
    "version": "1.14.4_HD_U_F5"
}