Once Paraview 5.10 has been installed, go to ‘Manage Plugins’ under Tools. There should be a plugin called AnalyzeNiftiReaderWriter that you can load in. If it is not there, you can download AnalyzeNiftiReaderWriter, select ‘Load New’, select the file you downloaded, and it should then appear.

Once again, this is in version 5.10.1, meaning that the Tools bar may already look different in the later versions (e.g. the OpenVR plugin in 5.10 is known as the XRInterface in 5.11).