Follow the below steps to create a team in CRM
Navigate to the Admin page
Select Team Management
Click the Drop Down next to the Module Name
Click Create Team
Enter Name and Description
Click Save
Click the new Team Name
Click Select to now select users to add to the team
Click Save
Regarding using teams to limit what users can see, the basic principle is "A user can only see a record if they belong to a team that is on the record". Admin users are exempt from this rule. See below for an example:
There are two accounts in your system: Account A and Account B.
Account A has two teams on the record: Midlands and Sales
Account B has two teams on the record: North East and Sales
A user who is in the Sales team only will be able to see both accounts.
A user who is in the Midlands team only will only be able to see Account A
A user who is in the North East team only will only be able to see Account B
It is possible to add a user to multiple teams as well. So if a user was added to North East and Midlands then they would be able to see both accounts.