how to extract the number of stories or bugs that a person engaged in

[Tahereh Mirzaee]

I Have several stories and bugs that several persons work on each. and the story or bug, itself has been assigned to few people but sub-task assignees are different. 

I want to know the number of story or bugs that person A is engaged in by being assigned to their sub-tasks. 

[Nic Brough -Adaptavist-]

Run a search for the issues you want to report on, then save it with a sensible name, and then use it in dashboard gadgets.

A simple gadget for "filter statistics" will give you the basics.  In the config for that, select your saved filter, then "assignee" as the statistic.  That will show you number of assigned issues per user (I'd probably set "include resolved issues" flag to "no", so it's only open issues in the report)

I'd also consider a couple of "2 dimensional" gadgets.  They work the same as the filter statistics, but they ask for two statistics and give you a grid cross-referencing them.  I'd want a look at Assignee vs Issue Type, and Assignee vs Status, probably on the same dashboard, side-by-side.