How to Change Gamerules in an Already-Created World with Preferred Gamerules

Open the Config Screen

Once the mod is installed, you no longer need to start a fresh world just to flip a gamerule. Load into the world you want to change, then open the Mod Menu config screen for Preferred Gamerules. From the mod list, find Preferred Gamerules and click its config button. The screen lists the world's gamerules as toggles and options, so you can edit them directly instead of typing commands.

Adjust and Apply

Scroll through the list and find the gamerule you want to change — for example, the day-night cycle, mob spawning, or weather. Toggle it or set its value to what you want. When you are done, save or apply the config so the change is written to the world. The new setting takes effect immediately in the loaded world; you do not need to recreate it or reload from the main menu.

Things to Keep in Mind

Because the mod edits the world's stored gamerule data, the change persists for that world across sessions. If a gamerule does not appear to update, close and reopen the config screen to confirm the value saved. This is the whole point of the mod: gamerules that vanilla only exposes at world creation become editable at any time, without needing command access or cheats enabled.