Multiple cluster support appears missing

[stuart-k-h]

According to the setup documentation it reads as if only a single cluster can be defined within the platform at any given time. As it is feasible for multiple clusters to exist, and there to be a desire to search multiple clusters by specifying the 'cluster=' parameter shown in the screenshots, this functionality should be added. If this functionality already exists, the documentation should be updated to clearly state that multiple clusters can be added and leveraged at the same time, including screenshots for reference (to avoid any confusion).