In your picture it appears you’re in “solid view” instead of material preview or rendered.
Normally you’d probably want to be in material preview to see how things look. (Rendered is nice but uses more resources.)
Up at the top right of your screen where you see the 4 circles next to a drop down you can select wire frame, SOLID – which you’re in, material preview, or rendered.
Edit: You have to pick material preview in both windows.