To take a screenshot with Windows 10
Press the keys: <Windows> + <print screen>.
You will find the picture file in the folder "Pictures/Screenshots/".
To take a screenshot with MacOS
Press the keys: <shift> + <command> + <3>.
You will find the picture file in the Desktop.
In our forum, post a link to download the picture file via an image hosting service.
Some image hosting service:
imgbb
Postimages