There is no way to install those drivers as the proprietary Catalyst driver is no longer being developed by AMD, and is not supported on the new X server or Wayland. There is the new AMDGPU driver which is automatically enabled, but it only works with new AMD video cards. Also, AMD has absolutely no plans for supporting the pre-GCN GPUs (lower than the 7600/8400 series) with the new AMDGPU driver see here
. Your only choice is to use the open source radeon driver, which is installed and enabled by default with the kernel.