If you've got an image you want to use as your background the simplest solution is to create a sprite and put and put the image into that.
You don't need to worry about collisions yet. Objects with collisions won't block character movement, only items with the "solid" behaviour will.
I don't think you need the tilemap object, the "tile movement" is a behaviour you can apply to sprite, etc. it doesn't actually need a tilemap.
I made a quick example of the tilemap plugin and tile movement behaviour for you.
The tilemap has 1 white and 1 black tile, which I've just painted as a chess board like grid. Then for a character I've created a sprite, which I painted red. I attached the tile movement behaviour to the sprite, and tweaked the positioning so that it sits in the middle of a space.