Hi,

You can create the dashboard using kanban view and from the templates. 

UPDT: You can check this video to see how to create a dashboard easily in Odoo: How To Create a Dashboard In Odoo

Have a look at the link to see how dashboard is created from the kanban view: https://webkul.com/blog/creating-odoo-custom-dashboard/

Also there is some free dashboard modules available in the odoo app store. You can refer the coding done for those modules also.

http://www.odoo.com/apps/modules/10.0/hr_dashboard/

Thanks