Demo Website for the simulation of a platform

I am working on my new startup which has a platform for the customers to choose investments and once invest they will have their own dashboard to monitor their investments, etc..Before I go live, for this platform I need to build a dummy interactive website with dummy numbers and investments to show the potential customers and investors how the platform or the system will operate and work. This is going to be like a demo version or a prototype of the service that will be offered. I need any expert advice on how to go about building this demo website with dummy data.

Thanks in advance, Rimzan