So, when Ohanacraft was first looking into updating to 1.14 we made a Vanilla+ world for everyone to experience a vanilla server with minimum plugins and commands. We have since shut down that world so that we can make room for new and more exciting things on OC! You can download the world folders (world and world_nether) to your computer from our Downloads page at http://ohanacraft.com/texture-pack-other-downloads/
So if you want to continue your build from vanilla you can load the folder onto your computer and set it up in a single-player world.