Hi,

As per your query in order to restrict visibility of opportunities for each user i.e. each simple user (salesman) would be able to see only those opportunities belonging to his/her sales team and not those of other sales teams. The following process can be followed to configure so :-

1) First you would be required to create an user by logging in with admin and going to Setting>Users>Users

2) Here while creation of the new user, under tab Access Rights , in the drop down type field Sales, we need to select “See Own Leads”,which satisfies your query.

3)Post this we need to go to Groups by following Setting>User>Groups. Here we can cross check if the user which has been created has been assigned with access rights or not. This can be done by searching for the group name Sales/See Own Leads, under the column heading Group names

4) By clicking on the group name as mentioned above, you would be able to see the user which you have created under the heading Users along with the admin. The admin would always be present as one of the user as he has super rights for everything. You would also be able to see the rights which has been offered to the user by clicking on the Access Rights.

Hope this helps

 Cheers!!