Hi Wolfram,
If you only want average B-factors and atom counts, you can click the magnifying glass in the PDB Tools GUI next to the model file name. That will give you general statistics about the file. Click on the "B-factors by chain" button to get the average B-factors.
For more information, you can run the "Comprehensive Validation" tool in the GUI with just the model.
From a terminal, you can run "phenix.molprobity <model file>" to calculate basic statistics. There will be a "Model Properties" section in the log and in "molprobity.out".
Let us know of any other issues. Thanks!