WCF Rest Servive

Dear All,

 

 I am creating a wcf rest service that returns data in JSON format. I created it and it works well in Dialog of visual studio and returns result in json format.

But if i tries it in browser of entering url like http:localhos:1120/Candidate.svc it runs. but it not shows its method. like http:localhos:1120/Candidate.svc/GetAllStudent (it is Service method.) it shows nothing. and also i clearly not come to know about certains  tag that we mention in web.config like :