Enums are generally used for creating custom types with a limited set of values:

1. Create an enum in solidity with the enum keyword:

enum Direction {
    // Options
}

2. Enums should contain at least one member:

enum Direction {
    North,
    East,
    South,
    West
}

3. You can initialize enums directly:

Direction path = Direction.North;

4. Enums support explicit conversion to and from all integer types:

function getCurrentChoice() view public 
    returns (uint) {
    return uint(path);
}

5. Use the following contract as an example of enums:

pragma solidity ^0.4.23;

contract Navigation {

    // enum declaration
    enum Direction {
        North,
        East,
        South,
        West
    }

    // Default direction
    Direction path = Direction.North;

    // Function which accepts enum as input
    function changeDirection(Direction dir) public {
        path = dir;
    }

    // Function which returns enum. Since enum is not part of ABI, return type will be changed to uint
    function getCurrentDirection() view public 
        returns (Direction) {
        return path;
    }
}