The usage of applications could you find within the session-logs and the usage of objects and selections will be logged in the audit-logging. All these loggings needs to be enabled within the qmc and there are already tools which could read these log-files. For this have a look on QlikView Governance Dashboard.
The QlikView governance dashboard is awsome, here you have the document and the documentation for loarn about it.
And you have all the information about user name, dashboard open it, at what time is open the dashboard, what browser is used by the user etc etc etc.