Can not add colour to my 3D model

After following the tutorials and creating a drawing in 3D, I have that I can not add colour to it.
I have noticed though that I am not getting the activatiation icon at the side of the bucket when you press shift or alt or control. What is wrong please? Ps I am on the trial version

Maybe you have set the Monochrome view- which don’t show colors or textures in the model. The activation icons show only when you have the cursor over a face.

Go to ‘view’, ‘face style’ and check ‘shaded with texture’ or ‘shaded’.