Just write down all your ideas that you've come up with and all the titles that you've been exploring. I put 3 possible working titles for mine. In the box below it where you outline all the different ideas for research and development, just put in everything that you want to look into or are thinking of looking into. This can be bullet pointed or paragraphed, whatever you like to help get you organised. In your planning review you just need to set yourself deadlines for different things, e.g "have research done by xxx" or "have first draft ready for xxx." It's meant to be a planner type thing, and it's meant to show that you can work to deadlines and it shows you've thought about how much time things take.
The log from what I can remember is worth a good deal of marks and my supervisor told me the best logs show a development of thought. So your log should show your changing thought processes as you go through and complete the project. Best way of doing this is to make each section as detailed as possible and not touch it again, that way your ideas in 3 months time aren't influencing the ideas of today.
I wish you luck