Get ready to build.

Install Prism and sign in

Install Prism Launcher from its website. In Settings → Accounts → Add Microsoft, sign in with your own account that owns Minecraft Java Edition. A parent can help with a child’s account.

Each person playing together needs their own account with Java Edition access. Owning Java and Bedrock on one account does not share Java Edition with the family. See Minecraft’s family-sharing guide.

The download page and our updater need no login. Microsoft handles game sign-in through the launcher; it may occasionally ask you to sign in again.

Import the family profile

Download the profile ZIP above. In Prism, choose Add Instance → Import and select the ZIP. Name the instance Schema Builder.

In Prism’s Java settings, enable Autodetect Java version and Auto-download Mojang Java. This profile needs Java 21. Prism downloads the matching game, loader and runtime from their upstream sources.

Play together

Launch Schema Builder. Choose Multiplayer → Schema Builder family LAN. Everyone must be on the home network.

If you need to add it manually, the address is 192.168.2.149:25565.

Craft a hut brick with a clay brick and a stone-brick block, or a bridge brick with a clay brick and an oak plank. Right-click to throw. Try an open area first: the structure replaces blocks in its footprint.

Keep your mod compatible

For later mod releases, close Minecraft and Prism, then run the Windows updater. In Prism, right-click your instance and open its folder first; use the folder containing mmc-pack.json.

.\Update-Client.ps1 -InstanceDirectory "C:\path\to\Schema Builder" -ReleaseUrl "https://minecraft.dokinetix.com/latest.json"

Run this in PowerShell from the folder where you saved the updater, replacing the instance path. It checks the game and loader versions, verifies the mod download, and backs up the previous mod. Your other mods, settings and saves stay in place.

For a game or loader change, import the new family profile into a separate instance. If Windows blocks a script, use the manual option below.

Tell Dad what went wrong

In Minecraft, type /fixitdad what happened. It saves your location, held items, nearby blocks and game setup. Wait for the saved report ID, click it to copy, and give it to Dad. He can retrieve the report and work through a fix with Codex.