Locate the different museums, monuments, events, etc. that you want to attend. Organize 3 tours. Figure out a time schedule for each day. You want your tours to be approximately the same length for all 3 days. Remember you will want to stay longer at some attractions and don't forget to eat.
Prices are available on the Internet and many attractions are free.
Make a list or chart for your brochure. Make a draft of what your brochure will look like. Leave room for pictures. Find pictures on the Internet that you want to use in your brochure, copy them, and save them. Using Microsoft Word and images from the internet, scanned or the digital camera, create your brochure.