Add Members to Groups in SharePoint 2010
For people to access your team site, you must add them to one of the default groups — Site Members, Site Owners, or Site Visitors. For example, to add someone to the Site Members group:
Log into the site as a site owner and then choose Site Actions→Site Permissions.
A list of SharePoint groups appears.
Click the Members group for your site.
A list of the users who are already group members appears.
Choose New→Add Users.
The Add Users page appears.
In the Select Users section, type the names of individual user accounts or domain groups in the Users/Groups text box.
Type the names in the form of domainaccount. For example, if your domain name is SP and the domain group name is Employees, type SPEmployees.
If you don’t know the names of user accounts, you can type the e-mail address. SharePoint tries to map the e-mail address for the account. For example, the e-mail address firstname.lastname@example.org resolves to SPEmployees in my domain. Chances are you can use the e-mail addresses from your address book in Outlook.
To search for user accounts, click the Book icon. Use the Select People and Groups dialog box to select user accounts.
If you can’t find the accounts you need, check with IT for assistance.
Click the Check Names icon to resolve the account names with the identity management system.
The Check Names icon is the check mark icon below the Users/Groups text box. When you click this icon, SharePoint tries to find the user account in the identity management system, such as Active Directory (AD). If SharePoint can’t find the user, you can’t add the account. If the names won’t resolve, see IT for assistance.
Use domain groups instead of individual user accounts to assign users to SharePoint groups. Check with IT to determine whether domain groups are available to meet your needs. However, if you just have a few people to add to your SharePoint group, it’s silly to ask IT set up a domain group. Just go ahead and manually add your users.