Required User Privileges: Company Admin
The first step is to click on Manage at the bottom left corner of SalesScreen.
A menu will pop up, where you can proceed to click on Users under the Company headline:
You will then reach the Users Management page. In the list, identify your user and click on the Name:
Once in the Edit user pop-up window, click on Access on the top navigation:
From there, you can select/deselect roles for the user to only grant him/her access to what you see fit. When you are done, click Save Changes:
Note that the changes will only be reflected within SalesScreen's interface once the user has refreshed his web-browser.