In the Sales module, your sales teams are accessible from the Dashboard menu. If you start from a new instance, you will find a sales team installed by defaul: Direct sales. You can either start using that default sales team and edit it (refer to the section Create and Organize your stages from the page Set up and organize your sales pipeline) or create a new one from scratch.
To create a new team, go to Configuration ‣ Sales Teams and click on Create.
Fill in the fields:
Enter the name of your team
Select your team leader
Select your team members
Don't forget to tick the "Opportunities" box if you want to manage opportunities from it and to click on SAVE when you're done. Your can now access your new team from your Dashboard.
If you started to work on an empty database and didn't create new users, refer to the page How to create a new salesperson?.