ASP.NET WebAPI WCF REST services async operations

Question

Hello All.......

I am new in Asp.Net Web development..........

I am assigned a project which is using WCF REST architecture, it is WEBAPI, Service, the methods of which are called in mobile apps(android, ios). Most of the methods uses async to perform database operations.

I am not able to understand when to use async and when not.

 

Can anybody help me/suggest me links to get familier with WCF RESTful WebAPI Services & most importantly async based operations(C#)?

Thanks in advance.

- Regards