Bathroom design

We are currently looking to start a project of bathroom ensuite redesign which involves a few changes to the current structure. The room is approx. 2 m x 2 m. We need to fit walk-in shower, sink, toilet, change lights and windows etc.
I would like to convey the proposed design to our builder. Please message with questions/details needed to be able to quote for the design mock-up more accurately.
Thanks
Martin