Two materials on one object I'm trying to do something simple and I know there are a few tutorials on how to do this but the steps set out don't seem to work for me.  What i want to achieve is a tile with an asphalt image texture on one side and a grass texture on the other.

The video shows the problem i'm having https://vimeo.com/239592554 although the resolution is not that great.

My workflow is:


select object and enter edit mode
select required face
type 'U' and unwrap face
create new material
select 'image texture'
find asphalt image and select
assign material
turn the object over and select opposite face
repeat steps 2 to 7 using the image of grass


The problem i have is that the grass then appears on both faces.  I can't see what i'm doing wrong but hopefully you can.  I'm using Cycles.

Many thanks in advance.

Stephen

Following helpful responses, I've tried with a fresh instance of Blender and a 'straight out of the box' mesh cube.  Then tried to add basic BSDF materials to separate faces but every time the material gets applied to the whole cube not just the selected face.

Could it be something to do with my Blender set up/user preferences?  I can't think what.  Anyway, gif of the new test included below:
You can perform a "double side material" node setup with the geometry node (selecting the backfacing option). The following image presents half a cube where the exterior is grass and the interior is gravel. The backfacing option uses the same UVmap but shows the texture for the other side of the faces, so from your steps, you can ignore step 8 and step 9. The same technique is used to create double sided pages, in a book or similar.