Functional Paths

Json Config Guide:

{
  "enabled": true,
  "blockSpeeds": {
    "minecraft:coarse_dirt": 1.1,
    "minecraft:gravel": 1.2,
    "minecraft:dirt_path": 1.3
  }
}

If you aren't using Mod Menu, you can configure this using the .json file.
It's pretty self explanatory, you put the block ID in quotes, tell the game what modifier you want the speed to be, and you're done.

When adding a new line make sure to add a comma, but on the last block you add do not add a comma at the end.

Ingame editing:

You will see 3 base blocks with their modifiers, that being dirt paths, gravel, and coarse dirt.

You can add custom blocks by pressing the insert new button on the lowest line, then in the empty spot below it you can enter what blocks you want.

The format goes as the following example: minecraft:stone=1.15, minecraft:moss_block=1.25