Generally speaking, what your supervisors want to see is that you are not completely lost, but instead have understood the problem and know where you are going. So my suggestion is to show them exactly that and convince them that you are on the right path.
From what you are writing, it sounds like you are doing good progress. Understanding the problem is usually the first big hurdle with PhD research. The second is defining one or more research objectives that are achievable with the resources and time you have available during your PhD.
You say you have already reviewed existing literature and started running experiments, so that should have given you a sufficient understanding of the current state of the art in your research field. What I suggest you do now is to try and define realistic research objectives that you believe you can achieve within the time at your disposal.
The layout you suggested sounds good to me. Include:
- introduction with description of the problem you are trying to solve
- previous research and existing solutions to the problem
- description of the experiments you have run and presentation of your preliminary results
- plan of research and the next steps you will take
Obviously, first consult any specific guidelines your faculty / department / research group might have regarding the preparation for this review presentation. Good luck!