secret-pony

You'll have to look for the printscreen key on your keyboard, it's often abbreviated as "Print Scr" or "Prt Scr" or something similar.
Paste the screenshot into your image editing software of choice, save the image and upload.

Thank you.

If you have time for it, feel free to post a screenshot.
It might be easier for me to understand the problem and see where it goes wrong.

This error message suggests you are using a lineart layer or your lineart layer is still active.
Make sure your color layer is active or use a regular layer for your coloring.
To make a regular layer, go to 'Layer > New Layer (N)' or click the blanc sheet icon (without the pen) in the layer toolbox.

When you select the bucket tool, check the settings that appear below your toolkit.
Under the "Target" section: If "all image" or "selection source" is checked, change it to "working layer"

I'm sorry, I have never used Photoshop before.