Sketching must be your first stage of any renovation work.
Pen and Paper is always best. Draw a plan and put it on one paper. At the bottom, at the Pros and Cons for each draw then you'll be able to compare them with each other better.
Floor Planner is an online tool to help sketching your floor plan. You'd need to have your measurements first.
Draw at least 5 plans and compare them with each other.
If you have a friend or family member or has more experience in sketching than you, you must ask their advice on your plans.