I created a world in Minecraft 1.13.1 and want to play that world on Minecraft 1.12.2 without losing my progress?

I'm using mac and am finding it quite difficult to do this

Can anyone explain to me how I can transfer my saved world to an older version?

Thanks

Read more: https://minecraftzone.net/qa/i-created-a-world-in-minecraft-1-13-1-and-want-to-play.html