You have two research pages. One is breaking down the design principles of each poster with how and why those principles have been used.
The second part is evaluating what are the positive and negative aspects of different design types.
You need to come up with four different concepts for your poster layout. Think about the different elements you will put on your poster, how many images, the floor plan, photos of the site, text, etc.
Take photos of your work as you are doing it. Use this as evidence of your thinking. For example if you are putting your title on your poster, don't glue it down. Try it in a couple of locations. If you are doing it on the computer, screen shot your work and print it out. Explain what you have changed and why.
Take photos of your presentation. Then write up a final evaluation of your work. Explain the process you went though, how you applied design principles to this, what you like, what you don't like, and they key works are because and why. Make sure you explain yourself and your decision.