I was only able to do this… more advice…thanks
model = Sketchup.active_model
entities = model.active_entities
# Input.....
larghTop = 52.cm
altTop = 71.5.cm
spessTop = 2.cm
# Create "layer"..."piano"...
layerPianoTop = model.layers.add("Piano Top")
model.active_layer = layerPianoTop
# Create "group"...
group_pianoTop = entities.add_group
group_pianoTop.name = 'pianoTop'
# Create a face and add it to the model entities
ptTop = []
ptTop[0] = [0, 0, spessTop]
ptTop[1] = [larghTop, 0, spessTop]
ptTop[2] = [larghTop, altTop, spessTop]
ptTop[3] = [0, altTop, spessTop]
face_top = group_pianoTop.entities.add_face(ptTop)
face_top.pushpull(-spessTop)
# Create a material and assign the texture to it
mat_TileA = model.materials.add("TileA")
fileName_TileA = File.join('Texture', 'TileA_10x10.png')
mat_TileA.texture = fileName_TileA
mat_TileA.texture.size = [19.685, 19.685] # Image(texture 'TileA_10x10.png') size in inches
# Assign the new material to our face we created
face_top.material = mat_TileA
# Move Texture....'TileA_10x10.png'....
pt_array = []
pt_array[0] = Geom::Point3d.new(larghTop,0,0)
pt_array[1] = Geom::Point3d.new(0,0,0)
on_front = true
face_top.position_material(mat_TileA, pt_array, on_front)