Answer for your first question
(For non public folder dashboards) Go to that dashboard stored dashboard Folder >> Click
Share option then you can mention the
Roles and internal subordinates options to share the dashboard into other users with access as
Answer for your Second question
I can guess following points are possible to missing,
Running User is missing in your dashboard. Please ask admin to set dashboard
Running User as
Specific user or
Login as user by clicking the gear icon for the dashboard
edit page. Which will decide which user context the dashboard data need to show.
If it's come from any package, please check the package access for the specific user.
Please check the dashboard component using
source report are coming from
public folder or any
shared folder. Because if
Source reports are stored in any specific
shared folder means, the users which view this dashboard need those report (
source report) access to view the dashboard components.
Please let me know if it helps.