Create a block with information regarding the number of comments and contents created in a specific group I am using Drupal commons 3.31.
I would like to know how many contents and how many messages are written within a group and  make a block out of it. Also be able to see how many comment,page a specific user has created.

Thank you
It sounds like this can be accomplished using the views module. Create a view of content from the group you are wanting, and then turn on aggregation. For each field, you can set it to display a count() of the field results.

For the per user part, just set up a filter/contextual filter for the UID.