Auto logout - idle timeout - how to?

please guide me to have Auto Logout after a specific idle time - no activity - may be some links can help too. and inform about what kind of issues/risks can be faced? like during a transaction entry boss called and user will  engaged with him/her etc. etc.
regards

Newbie here in CodeIgniter World !! Please appologize if any nonsense from me.  

environment: Windows 10, XAMPP 3.3.0, VS Code, SQLyog Community Ed. 

Perhaps something like https://stackoverflow.com/questions/1614...ng-codeign

with sessions

Practical guide to IgnitedCMS - Book coming soon, www.ignitedcms.com

thanks @ignitedcms for help. will check it. 
regards

Newbie here in CodeIgniter World !! Please appologize if any nonsense from me.  

environment: Windows 10, XAMPP 3.3.0, VS Code, SQLyog Community Ed.