How to redirect user after an alert message ?

ClientScriptManager script = Page.ClientScript;
if (!script.IsStartupScriptRegistered(this.GetType(), "Alert"))
{
script.RegisterStartupScript(this.GetType(), "Alert",
"");
}

What is sharepoint ?

Sharepoint is a microsoft technology which includes

Collaboration : A team of people working on a project to sharepoint information, documents to accomplish the golas.

Document Management : Manage and share documents through the use of versioning, metadata, workflows, search, profiles and information management policies.

Portal : An user interface that brings information together from different applications, and other sources such as web services and web sites.

Content Management : publishing and design processes for pages on portals and other web sites.