@JenJen type sudo apt install hyfetch
then when it's done, type hyfetch.
But to be fair the thing I really enjoy about customising linux, doesn't happen in the terminal.
Look for extensions, applets, and themes in the start menu
Look at hotcorners and workspaces and window tiling.
There's a lot of very immediate things.
I have an extension that burns a window up whenever I close it. It has other effects I recommend it.