How to implement Custom Setting in apex?

Hi Suraj

Custom settings are similar to custom objects and enable application developers to create custom sets of data, as well as create and associate custom data for an organization, profile, or specific user. All custom settings data is exposed in the application cache, which enables efficient access without the cost of repeated queries to the database. This data can then be used by formula fields, validation rules, flows, Apex, and the SOAP API.

You can use SOQL to query Custom Settings just like an object. Use a SQOL query to find the right value:

select yourfieldname from customsettingname
where fieldname = :someval and fieldname = :otherval

Suppose you have custom setting Games__c.

You can get the list of records through :
List<Games__c> mcs = Games__c.getall().values();

To get individual record 'My Games' of custom setting :
Games__c objGame = Games__c.getValues('My Games');

Hope it helps: