Newb Struggling with Tilemaps and Collision

I was following a RPG tutorial on YouTube which used Tiled and Tiled2Unity to create maps. Unfortunately those programs have changed too much since the tutorial was put up so it’s impossible for me to follow. So instead I’ve been trying to learn how to use the built-in tilemaps and I’m struggling mightily. I’ve got my Tile Palette set up and I’ve created on Tilemap which is my ground layer which I paint with a grass sprite. Then I create a new Tilemap, layered above the ground layer, and I draw in a flowerbox on that tilemap and add a Tilemap Collider. I can walk over the flowerbox still. Add a Composite Collider 2D and set the body type to static (otherwise it falls off the screen) and still I can walk through it. I’ve tried about a dozen permutations of steps and looked at half a dozen different tutorials which are use variously different methods but not once have I been able to create anything my player sprite colliders with. Is there a VERY SIMPLE from the BEGINNING tutorial out there on how to do this? All the ones I’ve watched seem to magically create the correct collisions simply by adding the collider without doing anything else. I’m at my wits end. Any advice would be appreciated.

@DoubleUU

I think you should start from the beginning, it’s explained well in official tutorials:

If it is too lengthy, see the post/gif I made: