Yes, this means that you have downloaded the open source version. In order for load balancing to work, you need to download RStudio Server Pro (the Professional version). There is a 45-day free evaluation period, and the documentation you pointed at is the best documentation that we have at present on load balancing.
If you have a chance to give things a shot prior to the call, please follow the directions at that link and keep tabs on any questions you have for us or share them here!
From a high level perspective, you will set up the appropriate file shares across servers and then configure the servers to know about one another. They will then take care of load balancing traffic using your configured load balancing scheme. You just need to route all traffic to a single node and let RStudio do the rest!
To download the professional version: https://www.rstudio.com/products/rstudio/download-commercial/