You have to click the Side bar menu & select the General Setting :
You get the page :  

Here you have multiple tabs. Now click on "MISC Setting" tab : 

On this page you have multiple configuration :
 - 1. Time Zone
 - 2. Email Duplication Allowed
 - 3. Contact Number Duplication Allowed

Time Zone : For update your time zone.

Email Duplication Allowed : This configuration used to allowed or not allowed to keep records of same email with more than one contact.
There are three option to set this particular configuration : 

Duplication Allowed : For allow to keep records of same email with contact.
For ex : In customers record you can associate one email with more than one customer. Or you can use that email to associate with even supplier also.
No Duplication Allowed For Same Contact Type : For allow to keep records of same email with same type of contact.
For ex : In customers record you can not associate one email with more than one customer. But you can use that email to associate with supplier.
Never Duplication Allowed : For don't allow duplication.
For ex : You can't associate one email with more than one contact even if it is supplier or customer or employee.

Contact Number Duplication Allowed : This configuration used to allowed or not allowed to keep records of same contact number with more than one contact.
There are three option to set this particular configuration : 

Duplication Allowed : For allow to keep records of same contact number with contact.
For ex : In customers record you can associate one contact number with more than one customer. Or you can use that contact number to associate with even supplier also.
No Duplication Allowed For Same Contact Type : For allow to keep records of same contact number with same type of contact.
For ex : In customers record you can not associate one contact number with more than one customer. But you can use that contact number to associate with supplier.
Never Duplication Allowed : For don't allow duplication.
For ex : You can't associate one contact number with more than one contact even if it is supplier or customer or employee.

After configuration :


After configuration in Misc Settings, now you have further move to set the Company Info .