That you can choose a colour, from the Color Pallette, then adjust it using the Colour inspector, then click on the colour add button to add it to the pallette.
You’ll see if you look at the layer names, that for a type of layer, say bitmapped, the name has to be unique. But for a different layer type the same name can be reused.
The joy is realising that you can learn from others, all you need is to be receptive to learning.