With this option you give your account manager access in the system and with the search option to the following possibilities:
Search in organization – Account managers can search throughout the organization, also in contacts of other account managers
Search in own teams – Account managers can only search in the contacts of other account managers in there team
Search in own company’s and contacts – Account managers can only search in their own contacts
The option: Limit administrators means that if you state that the admin and manager have the same restrictions as they also do sales themselves.