The best the way to start drawing your map is to look up reference images of the object you’re trying to build (in your case a city).
Once you find some buildings you like, map a general layout of the city. Do you want it in a circular shape? Square? Etc.
Draw a few quick designs and begin building the basic shapes, position them how you want, and then get into the details (materials, decorations, colors, windows, scenery, etc).
Keeping a list of what you want to do every day helps. Break each step into smaller, more manageable chunks.
Hope this helps!