sh_custom_achievements.lua

--[[
To create a new achievement you need to copy this code bellow.

do
    local achievement = {
        AchievementName = "New Achievement",
        Description = "Achievements description",
        Icon = "ldt_achievements/achievements/house.png",
        MaxProgress = 1,
        RewardAmount = 1000,
    }

    LDT_Achievements.RegisterAchievementsToCategory('General', achievement)

    if SERVER then
        hook.Add( "PlayerDeath", "LDT_Achievements.AchievementsName", function( victim, inflictor, attacker )
            if victim == attacker then return end
            if not IsValid(attacker) then return end

            LDT_Achievements.AddAchievementProgress(attacker, achievement.AchievementID, 1)
        end )
    end
end

The Name is the name that is displayed in the menu. IT HAS TO BE UNIQUE!
The Description is the description that is displayed in the menu.
The Icon is the icon that is displayed in the menu.
The MaxProgress is the amount of progress you need to complete the achievement.
The RewardAmount is the amount of money you get when you complete the achievement. If you don't want to give money set it to 0.

The hook.Add is the hook that is used to check if the achievement is completed.
You need to know what hook to use for the achievement you want to create. So a little bit of lua knowledge is required.
--]]