If you are missing the "Deals" button in top navigation menu, kindly note that this happens because you are not added/assigned as a user to any Workflow.
If you are not an admin user you will only be able to see deals of workflows you are added to as a member. This has to be performed by admin user and they need to go to:
Settings
Go to Workflows tab
Open workflow
Type your or the teammates name in 'Add team member' field
Select user from drop down
For this you can contact your team members that have admin access or us on: support@salestrekker.com