Draw an image on paper. I drew a tree. You can draw what ever you like. Now place it in your scanner, usually it is face down on the glass.
Import the picture from the scanner with Photoshop ( File > Import > (Scanner Name])
Scanner Settings
The setting on your scanner may vary but usually in most scanners the process goes like this:
There is usually a preview button to take a quick scan at a low resolution.
You click and drag a rectangle of what you want to scan. A moving dotted line should appear.
You then set your resolution. I usually recommend 200 dpi (dots per inch) as a good resolution.
Click the scan button and wait for your scan. If you are happy with the scan you can close the window by clicking the red x in the upper right hand corner to go back to Photoshop.
Saving a Document (File > Save As…)
Now you need to save the file just in case your computer crashes. The first time you save your file you use "Save As.." to give it a name and put it in a place. If you have saved a file in Windows before, than this window should look familiar to you. Be sure to name your file so it makes sense to you and save it as a .PSD
Once you have done this you can now use (File > Save) to save your work.