From the top of this very board: windows programming links. That should get you started.
A 'simple' text editor as you have described, at your current level of knowledge, would involve a main window with an edit control. To change the font you'd send the edit control a WM_SETFONT message, to change the colour of text(all of it) and background colour you would handle the parent's WM_CTLCOLOREDIT message.
The link above contains links to other resources that should get you started; search this board, too, for examples of the messages etc I have mentioned as there will be many examples and discussions of their use.
If you have problems with specific aspects of code then post your problematic code within code tags together with a description of the problem, the compiler you are using and any error messages you may have.
