I've been following a youtube tutorial on scene set up and character creation for AC, this one in particular:

I created all of my animations which work just fine. I also made a 2D NavMesh to try out my character, but when I play the scene, the character won't move up and down, just left and right.
The messages shown on the console are:
PlayerPrefs Key "AC_AdventureCreator_Demo_0" loaded
PlayerStart "PlayerStart2D" has no camera on start.
Comments
The error message is alerting you that your PlayerStart has no associated camera. Each PlayerStart in a scene needs a camera, so that the game knows which camera to start from.
In your Scene Manager, make sure that your created PlayerStart is assigned as the Default PlayerStart under the "Scene settings" panel. You can then assign an associated camera from the Default Camera field. You can click "Create" to the right of the "Default Camera" field to automatically create and assign one.
If you still have trouble with your character, try testing the 2D Demo game's Player prefab, Brain2D, by dropping him into your scene and running it. If he runs OK, but yours doesn't, post some details about your player prefab so that we can see what's wrong. If he doesn't run OK either, post some details of both your Scene and Settings Managers, which should help us get to the bottom of it.
The console is showing this message:
In order to move a sprite based character in 3d, there must not be a rigidbody 2d component on the base.
player cannot find sorting map to follow.